Stocks fell from an eight-week high on active trading, led by smaller companies, as investors diverged on the stock market rebound.
The Shanghai Composite Index closed at 3,320.68, down 3.1 percent, while the Shenzhen Component Index plunged 5.9 percent to 10,915.99.
Smaller firms ranging from software developers to machine manufacturers led the decline on Wednesday. Corporate management software and cloud service provider Yonyou Network Co amd Inspur Group Co tumbled by the daily limit of 10 percent.
The ChiNext index, which tracks China's NASDAQ-style board of growth enterprises listed in Shenzhen, dived 6.6 percent to close at 2,344.74.
Leshi Internet Information and Technology Corp and East Money Information Co, both heavily weighted ChiNext stocks, plunged 10 percent.
Despite the slump, trading volume showed signs of picking up after hitting a trough on the eve of the national holiday, with a total of 1.17 trillion yuan worth of stocks changing hands at the two market on Wednesday.
The CSI 300 Index slid 2.9 percent to 3,473.25.
