Document and Entity Information	3 Months Ended
	Dec. 31, 2011	Feb. 07, 2012
Document and Entity Information
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Dec. 31, 2011
Trading Symbol	cbak
Entity Registrant Name	CHINA BAK BATTERY INC
Entity Central Index Key	0001117171
Current Fiscal Year End Date	--09-30
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		63,816,276
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well Known Seasoned Issuer	No
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q1