Objective To evaluate the adherence and influencing factors of colorectal cancer CRC patients using electronic patient-reported outcome ePRO tool for symptom management during anti -tumor therapy. Method A retrospective analysis was conducted on data of 326 CRC patients recruited from 36 hospitals nationwide from January to November 2023. Adherence to ePRO tool during anti-tumor therapy was assessed using overall response rate ORR average response rate ARR single response rate SRR and patient-level response rate PRR . The generalized linear mixed model was used to analyze factors influencing the use of ePRO tool. Result During anti-tumor therapy ORR of CRC patients ranging from 31. 98% to 60. 36% and ARR from 31. 49% to 62. 09% across different ePRO tool modules. The mean PRR of CRC patients varied between 27. 33% and 51. 15% depending on the total number of treatment cycles. Higher adherence was observed in younger patients those with stage Ⅱ and Ⅲ CRC patients residing in rural areas and those receiving immunotherapy. Conclusion Adherence to ePRO tools during anti-tumor therapy in CRC patients in clinical settings is relatively low. To enhance the adherence of CRC patients to ePRO tools and thereby maximize their clinical utility in symptom management efforts should be directed towards strengthening patient education optimizing the design of ePRO tools and reinforcing the feedback mechanisms between healthcare providers and patients.