No purchase price has been disclosed for the group, which runs 13 stores in China with a further five due to open before the end of the year.
The addition of the stores, with a net asset value of about£85 million will increase B&Q's Chinese portfolio to around 50 stores within the next 12 months.
B&Q China had 2004/2005 sales of£212 million and retail profit of£5 million. It runs 22 stores in the country.
Kinfisher chief executive Gerry Murphy said: 'China is a tremendous opportunity for Kingfisher and this move underlines our commitment to the Chinese market.'