Objective To explore the effect of comprehensive clinical practice on nursing undergraduates' critical thinking.Methods A total of 350 nursing undergraduates were investigated with the California Critical Thinking Disposition Inventory-Chinese Version(CTDI-CV) before and after clinical practice.Results Through comprehensive clinical practice,the total score of CTDI-CV of nursing undergraduates was significantly lower after practice(P0.05).The scores of truth seeking,open-minded,system activity and maturity were significantly lower after clinical practice(P0.05).The grade and type of the practice hospital and practice time exerted no significant effect on the total score of CTDI-CV(P0.05).Conclusion Currently,comprehensive clinical practice is not helpful in improving nursing students' critical thinking.As a result,nursing schools and hospitals would enhance the management of practice teaching and attach importance to the development of students' critical thinking.