There are few reports on compliance with oral nutritional supplements (ONS) after surgery in hospitalized patients. This study aimed to investigate the compliance with ONS and its influencing factors after surgery in colorectal cancer patients. STROBE checklist was used during the preparation of this paper. A total of 103 postoperative colorectal cancer patients were selected from November 2020 to April 2021 from the Department of Anorectal Surgery in our institution, which is a tertiary hospital in Hangzhou, China. The compliance with ONS was recorded by a self-record sheet, and sociodemographic and disease-related information of these patients was gathered through a self-designed questionnaire. The overall ONS compliance rate of patients with colorectal cancer was 57.6%. Results of univariate analysis revealed that ONS compliance rate was related to sex, admission body mass index, abdominal distension, attitude towards ONS, and satisfaction with ONS. Multi-factor analysis showed that age, sex, and perceived benefits of nutrition therapy independently influenced the ONS compliance rate. The postoperative ONS compliance rate of colorectal cancer patients needs to be further improved. Healthcare professionals should pay more attention to the postoperative ONS compliance and acknowledging the influence of age, gender, and attitudes towards ONS on ONS compliance. Notably, patients' perspectives towards ONS play a crucial and modifiable role in determining ONS compliance. Nurses ought to assist patients in cultivating a positive attitude towards ONS. Dosage form and delivery method are also influence factors that deserves further exploration in the future. Future research endeavours should endeavour to craft tailored, meticulous nutritional intervention strategies tailored to the diverse factors that influence ONS compliance, ultimately leading to enhanced ONS adherence. Our findings could serve as valuable evidence for the development of strategies aimed at enhancing ONS usage practices.