Evaluating Master of Nursing Specialist (MNS) students' knowledge, attitudes, and practice regarding catheter‐related thrombosis (CRT) prevention and treatment is beneficial in developing effective CRT training for them. This study thus aimed to explore their knowledge, attitudes, and practice toward CRT. This was a cross‐sectional study that included 1046 MNS students in China. The results revealed that the median scores for the participants' knowledge, attitudes, and practice were 12 (interquartile range: 9–14), 55 (interquartile range: 50–65), and 62 (interquartile range: 51–71), respectively. There was a positive correlation between knowledge and attitudes, as well as attitudes and practice. Age, school level, proactively learning CRT knowledge, gender, enrolment method, participation in clinical practice time, and attendance at CRT training were related to knowledge (p < 0.05). Attendance at CRT training and experience using thrombosis risk assessment forms were related to attitude and practice (p < 0.05). Gender and experience caring for CRT patients were associated with practice (p < 0.05). MNS students have insufficient knowledge of CRT prevention and treatment, and the practice needs to be improved. However, their attitudes are positive.