This paper gives a method using virtual instruments technology to generate sonar signal by NI DAQ card and amplifying circuit[1]. This paper gives an example of generating CWP signal. In design of software, it generates signal by the way of timer querying and signal triggering. Existing method generates an array then delay to transmit. Method introduced in this paper, by contrast, is more flexible and has a higher degree of accuracy. Hardware design adopts stable and mature chips, to make sure the system can perform well in outfield. Multiple strobe circuits achieve a wide range of SL. High-fidelity integrated power amplifiers reduce the distortion of the signal during transmission and the introduction of noise[2].Compared with traditional sonar signal transmitter, the micro DAQ card and amplifying circuit can be put inside the industrial control computer, used as a portable sonar signal transmitter.