Objective: To understand the clinical occurrence and influencing factors of venous thromboembolisms related to implanted ports in cancer patients undergoing chemotherapy, and to construct and validate a simple risk scoring system, so as to provide reference for clinical nursing of cancer patients undergoing chemotherapy. Methods: The data of cancer patients undergoing chemotherapy in our hospital from January 2015 to December 2018 were retrospectively collected with self-designed patient information questionnaire. The data were analyzed by SPSS 22.0 software. Results: The incidence of venous thromboembolisms related to implanted ports in 620 patients was 6.5% (40/620), the incidence in training samples and validation samples were 6.7% (25/372) and 6.1% (15/248), respectively. After logistic regression analysis, the frequency of chemotherapy, cancer stage, thrombosis history, d-dimers and ipsilateral central venous catheterization history were included in the simple scoring system. The score of the model ranged from 0 to 28, which could be divided into three risk levels: low risk (<9), medium risk (9–19) and high risk (>19). There was no significant difference in the incidence of thrombosis between training samples and validation samples at different risk levels (P>0.05). ROC results showed that the area under the curve of training samples and validation samples was 0.748 (0.707–0.873) and 0.837 (0.749–0.925), respectively, and there was no statistical significance (P<0.05). Conclusion: The clinical incidence of venous thromboembolisms related to implanted ports in cancer patients undergoing chemotherapy is relatively high. The new simple scoring system has certain predictive ability and is suitable for the screening and prevention of port-related thrombosis in cancer patients undergoing chemotherapy.