Traditional PWM signal generators have problems with low accuracy and poor portability in signaregulation for mobile devices. In response to the current situation, a portable PWM signal generator has beerdesigned based on FPGA, which can achieve a duty cycle adjustable in 1% 6 step size and four frequeney pulswidth adjustable square wave signal generators of 100 Hz, 1 kHz,10 kHz, 100 kHz and can be controlled by foubuttons , and finally displayed on a digital tube with the minimum resolution. The experimental results show thathe signal generated by the system circuit is stable and reliable, and it also has advantages such as higlaccuracy and good portability.