Compared with traditional rockets and missiles, pressure fluctuation problems of reusable space vehicle are more complicated and few researches were carried out. By introducing RANS/LES hybrid method, this paper simulates the unsteady flow field of reusable space vehicle under typical modes including vertical status, transonic flight and supersonic flight, and extracts fluctuating pressure data from typical characteristic positions. The computing results show that, under vertical status, pressure fluctuation occurs at leeward area and separation point, sound pressure level (SPL) is around 115 dB, and frequency is no more than 1 Hz; fluctuating pressure occurs within shock oscillation zone of wings and tails at transonic speeds, SPL is around 140 dB, and frequency is around 10 Hz; fluctuating pressure of supersonic flight happens at windward area of vehicle's wings and ailerons, where high adverse pressure gradient is observed, SPL is also around 140 dB, and frequency is around 22 Hz. Moreover, vehicle base where separation occurs also has stronger fluctuating pressure.