A simulator for developing an acoustic detector of underwater vehicle precisely verifies performance of an acoustic detector by simulating an actual underwater environment, including target signal, applied to an underwater vehicle. The simulator an I/O communication unit for receiving information required for simulating an underwater environment from an acoustic detector and an motion simulator; a signal generator for receiving the information from the I/O communication unit to calculate a digital signal model; a D/A converter for converting the digital signal model into an analog signal; a signal conditioner for generating a signal similar to the signal of an actual underwater environment by controlling frequency and gain of the analog signal; and a remotely controlled computer for loading an OS to the signal generator and displaying various operation status.