Background Integrative Chinese and western medicine (ICWM) is commonly used for the treatment of ulcerative colitis (UC) in clinical practice. However, it is unclear whether the details of ICWM interventions, such as selection rationale, implement design and potential interactions, were adequately reported. Therefore, this study aimed to assess the quality of reporting in the ICWM interventional randomized controlled trials (RCTs) of UC, and to identify the common problems if any. Methods Through a search of 10 international electronic databases, we identified RCTs of UC with ICWM interventions published in English or Chinese up to 23 February 2022. The general characteristics of included studies were described. The quality of reporting was assessed according to three checklists, including the CONSORT (Consolidated Standards of Reporting Trials) with 36 items (except for one item 1b about abstract), the CONSORT for Abstracts (17 items), and a self-designed ICWM-related checklist (27 items covering design rationale, intervention details, outcome assessments and analysis). The reporting scores of RCTs published before and after 2010 were compared. Results A total of 1,335 eligible RCTs were included. For the reporting compliance, the median score (interquartile ranges) of the CONSORT (72 score in total), the CONSORT for Abstract (34 score), and ICWM-related (54 score) items was 29 (26–33), 18 (14–21), and 13 (11–15), respectively. In addition, more than 50% items were evaluated as poor quality (reporting rate < 50%) among each checklist. Time period comparisons showed that reporting quality of included publications improved signifcantly after the CONSORT 2010 issued (P < 0.01). Conclusion Although CONSORT appears to have enhanced the reporting of RCTs in UC, the quality of ICWM specifics is variable and in need of improvement. Reporting guideline of the ICWM recommendations should be developed thus to improve their quality.