They said the tone was uncertain and not helped by the institutional investor selling, which raised some concerns about a possible lack of confidence in the economic outlook.
The Shanghai A-share Index fell 20.09 points to 1,179.48 on turnover of 7.99 billion yuan (985.20 million dollars) while the Shenzhen A-share Index was down 5.10 points or 1.74 percent at 288.40 on turnover of 4.89 billion yuan.
The benchmark Shanghai Composite Index, which covers both A- and B-shares, lost 19.25 points or 1.69 percent at 1,121.92 on turnover of 8.05 billion yuan.
The Chinese yuan closed at 8.0901 to the US dollar, up from its previous finish at 8.0916.
Automakers in particular were hit by the selling pressure given concerns about their earnings outlook in an fiercely competitive industry.
Hunan Changfeng Motors lost 0.28 yuan or 6.25 percent to 4.20, Chongqing Changan Automobile, a partner of Ford Motor, fell 0.14 yuan or 3.15 percent to 4.31 and Dongfeng Automobile shed 0.06 or 2.18 percent to 2.69.
Jiangling Motors, another partner of Ford, slipped 0.05 yuan or 0.88 percent to 5.62 even though it said its net profit for the third quarter rose 36 percent year-on-year.