Abstract: Considering the influence of risk factors, correlation and non-dominant lines on the duration, a BN-PERT project schedule risk analysis model based on Bayesian network (BN) and modified project evaluation and review technique (PERT) is established. On the basis of schedule development and risk BN, the optimistic coefficient is introduced into the model to reflect the preferences of decision makers; then, the linguistic variables are used to describe the grade judgment of experts, the fuzzy numbers are used to convert the linguistic variables into probability values, and the probability reasoning function of BN and the modified PERT are used to analyze the expected duration and the completion risk rate. The analysis of engineering examples shows that the calculation results of the BN-PERT model reflect better the objective properties and characteristics of engineering risks.