This study was undertaken to assess the critical thinking dispositions of undergraduate college students in a comprehensive university of mainland China and examine the roles of gender and major in the subjects' critical thinking dispositions. An adapted Chinese version of the California Critical Thinking Dispositions Inventory (CCTDI) was used to survey 534 undergraduate students. Statistics revealed that over 3/4 of the subjects were negative in their dispositions to think critically, and no more than 1/4 of them were positive. All the subscale mean scores were between 30-35, indicating an ambivalent attitude to critical thinking. Meanwhile, the subjects were stronger in systematicity, truth-seeking, and self-confidence than in analyticity, inquisitiveness, and cognitive maturity. Besides, males got significantly higher scores in overall critical thinking dispositions, truth-seeking, cognitive maturity, open-mindedness, and justice-orientedness, an added subscale in the Chinese version of CCTDI. Finally, science-engineering students achieved a non-significant higher overall mean score than non-science-engineering students. They also scored higher in seven out of the eight subscales, but the differences were only significant in open-mindedness and justice-orientedness.