The CSI300 index of the largest listed companies in Shanghai and Shenzhen fell 2.2 percent, to 3,237.00, while the Shanghai Composite Index lost 2.1 percent, to 3,086.06 points.
Tokyo stocks closed 1.43 percent higher on Thursday, swept up in a global rally hours ahead of the US Federal Reserve's hotly anticipated interest decision.
The CSI300 index rose 0.3 percent, to 3,320.54 points at the end of the morning session, while the Shanghai Composite Index gained 0.5 percent, to 3,168.31 points.