Abstract: According to the production situation that the pressure in one frame unit of continuous hot press was uniform, a singleopening hot press was applied to simulate the working status of different frame unit for investigating the properties of fiberboards with different thickness(7.8 mm and 10.8 mm) under two kinds of pressure curve(P1,P2). The results showed that P1 was better than P2 when thickness of fiberboard was 7.8 mm; P2 was better than P1 when thickness of fiberboard was 10.8 mm, and at this time all the properties of fiberboards which started from frame 36 under both pressure curves were in accordance with national standard of fiberboard. Moreover, the starting position of applying pressure in the whole of frame units was related to the thickness of fiberboard. The thinner the thickness of fiberboard, the earlier the applying pressure.