In this paper, the transmission performance of soliton communication system using phase-sensitive amplifiers (PSAs) as in-line amplifiers was theoretically analyzed by computer simulation. For comparison, we also simulated the transmission performance of soliton system using erbium-doped fiber amplifiers (EDFAs) as in-line amplifiers. Our simulation considered both average-soliton regime and dynamic-soliton regime. The simulation results show that due to no ASE noise in PSAs, using them as in-line amplifiers in soliton system, the Gordon-Haus restriction can be overcome and soliton interaction can be greatly suppressed. For average-soliton, in the condition of no additional soliton control techniques, the soliton steady transmission distance can be lengthened greatly. For dynamic-soliton, PSA also has a good behavior of suppressing pulse broadening and soliton interaction. But after long distance transmission, the amplitude of soliton pulse descends significantly.