Background Body image is a complex post-treatment concern among female patients with breast cancer, and various tools have been developed and applied to measure this multifaceted issue. However, these available tools were developed in other countries and only a few have been modified into Chinese versions. Furthermore, body-image evaluation instruments that are specific to Chinese mainland female patients with breast cancer have not been devised yet. Therefore, we developed the Body Image Self-rating Questionnaire for Breast Cancer for Chinese mainland female patients with breast cancer. Methods We performed two rounds of the Delphi technique and a cross-sectional pilot survey. Items were selected using a Likert scale (1–5) to determine ratings of importance (i.e., the significance of the item from experts’ perspective; coefficients of variation ≤0.25), internal consistency reliability (Cronbach’s α ≥ 0.70), convergent validity (hypothesized item-subscale correlations ≥0.40), and discriminant validity (stronger correlations of the item with the hypothesized subscale than for other subscales). All decisions on items were made based on statistical analysis results, experts’ recommendations, and in-depth discussion among researchers. Results Twenty-five eligible experts completed the two Delphi rounds (mean age: 42.20 ± 8.90 years). Over half the experts were professors (56%, n = 14) or worked as clinical staff (68%, n = 17). Twenty (mean age = 49.55 ± 10.01 years) and 50 patients (mean age = 48.44 ± 9.98 years) completed the first- and second-round survey, respectively. Over half the patients had a tertiary education level, were married, and were employed. Regarding the revised questionnaire (comprising 33 items across seven subscales), the expert panelists’ ratings of each item met the criteria (Kendall’s W = 0.238, p < .001). Five subscales had a Cronbach’s α value over 0.60 (range: 0.62–0.69) and two subscales were over 0.80 (range: 0.84–0.88). All items satisfied the criteria for convergent and discriminant validity. Conclusions The findings of this study provide evidence of a suitable tool for body image evaluation among Chinese mainland female patients with breast cancer. Studies with larger sample sizes should be conducted to validate this questionnaire in this patient population. Electronic supplementary material The online version of this article (10.1186/s12885-017-3865-5) contains supplementary material, which is available to authorized users.