ZAI LAB LIMITED

(Name of Issuer)

Ordinary Shares, Par Value $0.00006 Per Share

(Title of Class of Securities)

98887Q104(1)

(CUSIP Number)

December 31, 2018

(Date of Event Which Requires Filing of this Statement)

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)   Ying Du
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  [  ] (b)  [  ]
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION   United States of America
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER  9,399,0891
	6	SHARED VOTING POWER  0
	7	SOLE DISPOSITIVE POWER  3,315,434
	8	SHARED DISPOSITIVE POWER  0
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON  9,399,089
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)  [   ]
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)   15.58%2
12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)  IN

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Item 1(a).			Name of Issuer:   Zai Lab Limited (the "Issuer")
Item 1(b).			Address of Issuer's Principal Executive Offices:   4560 Jinke Road, Bldg. 1, 4F, Pudong, Shanghai, China 201210
Item 2(a).			Name of Persons Filing:   Ying Du
Item 2(b).			Address of Principal Business Office or, if None, Residence:   4560 Jinke Road, Bldg. 1, 4F, Pudong, Shanghai, China 201210
Item 2(c).			Citizenship:   United States of America
Item 2(d).			Title of Class of Securities:   Ordinary Shares, par value $0.00006 per share
Item 2(e).			CUSIP Number:   98887Q104
Item 3.			If this statement is filed pursuant to Rule 13d-1(b), or 13d-2(b) or (c), Check Whether the Person Filing is a:   Not applicable.
	(a)	[    ]	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).
	(b)	[    ]	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).
	(c)	[    ]	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c).
	(d)	[    ]	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8).
	(e)	[    ]	An investment adviser in accordance with §240.13d-1(b)(1)(ii)(E);
	(f)	[    ]	An employee benefit plan or endowment fund in accordance with §240.13d-1(b)(1)(ii)(F);
	(g)	[    ]	A parent holding company or control person in accordance with §240.13d-1(b)(1)(ii)(G);
	(h)	[    ]	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
	(i)	[    ]	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
	(j)	[    ]	Group, in accordance with §240.13d-1(b)(1)(ii)(J).

Item 4.	Ownership.
	(a)	Amount Beneficially Owned:   See the response to Item 9 on the attached cover page.
	(b)	Percent of Class:   See the response to Item 11 on the attached cover page.
	(c)	Number of shares as to which such person has:
		(i)	Sole power to vote or to direct the vote:   See the response to Item 5 on the attached cover page.
		(ii)	Shared power to vote or to direct the vote:   0
		(iii)	Sole power to dispose or to direct the disposition of:   See the response to Item 7 on the attached cover page.
		(iv)	Shared power to dispose or to direct the disposition of:   0
Item 5.	Ownership of Five Percent or Less of a Class.
	If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than 5 percent of the class of securities, check the following [  ].
Item 6.	Ownership of More than Five Percent on Behalf of Another Person.
	Certain holders of the Issuer's ordinary shares, including Zai Lab Limited management and their affiliates, have granted Dr. Du the right to vote 6,083,655 ordinary shares. Although Dr. Du does not have any pecuniary interest in these ordinary shares, she may be deemed to be the beneficial owner of the ordinary shares held by these shareholders.
Item 7.	Identification and Classification of the Subsidiary which Acquired the Security Being Reported on By the Parent Holding Company or Control Person.
	Not applicable.
Item 8.	Identification and Classification of Members of the Group.
	Not applicable.
Item 9.	Notice of Dissolution of Group.
	Not applicable.
Item 10.	Certification.
	Not applicable.

	/s/ Ying Du
	Ying Du