Abstract Background Colorectal cancer (CRC) is one of the most prevalent cancers, and the risk of CRC is substantially greater in a high-risk population than in the general population. However, no existing assessment instruments have been specifically designed to evaluate CRC prevention behaviors in a high-risk population. The aim of this study was to develop and psychometrically validate an information-motivation-behavioral skills (IMB) questionnaire tailored for the population at high risk for CRC (IMB-CRC) to assess the factors influencing prevention behaviors. Methods This cross-sectional study was conducted in northeastern China. The initial questionnaire items were derived from a comprehensive literature review, semistructured interviews analyzed via content analysis, and expert focus group discussions. Content validity was assessed through expert consultation using the Delphi method, and face validity was evaluated in the high-risk population for CRC. Explanatory factor analysis (EFA) was performed on Sample 1 (N = 287) to identify underlying factors, and confirmatory factor analysis (CFA) was performed on Sample 2 (N = 224) to validate the model. Internal consistency and test-retest reliability were also examined to ensure the stability and consistency of the questionnaire. Results The final IMB-CRC comprises 21 items distributed across four dimensions: prevention information (7 items), objective skills (5 items), self-efficacy (5 items), and motivation (4 items), collectively accounting for 61.99% of the variance. CFA indicated that the proposed model fit the data well (χ2/df = 1.779, RMSEA = 0.059, AGFI = 0.852, GFI = 0.883, CFI = 0.950, IFI = 0.951, TLI = 0.943, and NFI = 0.894). The item content validity index (I-CVI) for individual items ranged from 0.905 to 1, and the scale content validity index (S-CVI) was 0.952, suggesting good content validity. The IMB-CRC demonstrated high reliability, with a Cronbach’s alpha of 0.937, McDonald’s omega of 0.939, and test-retest reliability of 0.919. Significant positive correlations were observed between the IMB-CRC and each of its four dimensions, indicating that higher IMB-CRC scores were associated with greater engagement in cancer prevention behaviors among the high-risk population. Conclusion The IMB-CRC exhibited appropriate validity and reliability, indicating that this questionnaire is a robust tool for assessing behavioral components essential for CRC prevention in the high-risk population. Health care professionals and policymakers can use the IMB-CRC to develop targeted CRC risk communication and behavioral education strategies, thereby improving the preventive abilities of a high-risk population.