Abstract: During the operation of the secondary loop system of nuclear power plant, the condenser is an important cooling source and serves as the final heat removal equipment of the whole thermal cycle. The startup progress of the condenser is the mean part of condenser operation test. In this paper, the physical model for the condenser is first established and the mathematical model for the dynamic simulation of the condenser startup process is built with simplified assumptions. PID control is used for the condensing water outlet valve and the circulating cooling water inlet valve during the startup process. The operation characteristics of the startup process are studied with the condenser simulation model. Through the simulation of the startup process, the variation characteristics of mean parameters with time could be obtained which are relatively stable without oscillations. The valve position change of the condensing water outlet control valve and circulating cooling water inlet control valve could also be simulated in this progress. After the startup, the condenser steady-state parameters have little error compared with design data. The simulation model and startup control process could provide reference for actual condenser operation.