This study aimed to explore the correlation between the rumination thinking and the status of career maturity in clinical practice nursing students. With the stratified convenient sampling method，868 nursing undergraduates， higher vocational （three?year） and higher vocational （five?year） students were selected from twelve hospitals in Nanjing from June to December 2018. The general data questionnaire， the career maturity inventory （CMI） and the ruminative response scale（RRS?10） were used. Results showed that the average level of occupational maturity of 868 clinical nursing students was 3.07±0.28， in the middle level; The average level of rumination was 22.71±4.70， among which brooding （12.05±2.58） was higher than reflective pondering （10.67±2.48）; The rumination of nursing students was positively correlated with their career maturity. The nursing students in clinical practice mostly have rumination thinking which affect their career maturity. In the teaching of clinical practice， nurses should pay attention to students’ mental health， guide the students who have experienced negative clinical events actively and advantageously， help them to transform the forced thinking into introspective thinking， and then improve their career maturity level.