Objective To analyse the influencing factors for critical thinking ability of students majored in clinical medicine and nursing, and provide referrences for critical thinking ability cultivation in medical students. Methods A total of 590 students majored in clinical medicine and nursing were selected by cluster sampling method, and questionnaires of Critical Thinking Disposition Inventory-Chinese Version (CTDI-CV) were adopted for survey. With critical thinking ability as dependent variable and general conditions and related variables (gender, grade, major, educational background, only child, religious belief, family information, census register, health condition, part-time job, time of extracurricular reading, loving one's profession, practical training, sense of achievement, understanding of critical thinking ability and personality) as independent variables, influencing factors for critical thinking ability were screened with multiple linear regression analysis. Results Critical thinking ability was significantly related to sense of achievement, time of extracurricular reading, understanding of critical thinking ability and religious belief in medical students (P<0.01). Conclusion Cultivating sense of achievement, enhancing extracurricular reading ability, deepening understanding of critical thinking ability and establishing a scientific world outlook and methodology may be effective ways to develop critical thinking ability of students majored in clinical medicine and nursing.