Objective: To Understand the mastery level of diabetes knowledge for clinical nurses in tumor hospital.Methods: A questionnaire survey was conducted among 111 nurses in Shandong Tumor Hospital. Results: The average score of diabetes knowledge was 23.22±2.70, and 21.5% of that was better. There was statistical significance different in various technical title, multilevel nursing，service year, and the number of diabetes patients（P<0.05）. The mastery degree of knowledge of diabetes complication was lower, the error rate was 65.42%. Conclusion: The nurses in tumor hospital, especially junior nurses, should be trained in further specialized diabetes knowledge.