For the complex construction process， high risk probability during the construc-tion， unpredictable development situation with traditional risk assessment methods of pre-fabricated buildings， five influencing factors which are human factors， equipment and mate-rials， construction technology， safety supervision and management， and surrounding envi-ronments are considered comprehensively， the membership function of the sample to bee-valuate dis determined， the weight of the security risk assessment index is calculated by the subjective and objective combination weighting method using the analytic hierarchy process and the entropy weight method， a safety risk assessment model is established to evaluate the construction safety risk of prefabricated buildings based on the similarity， difference and counter analysis， and the set pair theory is used to analyze the fourth-order development trend of the index.The results show that the safety risk of the example project is medium，which is consistent with the survey results.The evaluation method can truly and reliably reflect the fuzziness and randomness in the process of safety risk evaluation of prefabricated buildings and improve the accuracy.This comprehensive evaluation model can not only de-termine the construction safety risk level of prefabricated buildings， but also accurately pre-dict the trend of risk， and realize the effective combination of static evaluation and dynamic evaluation.