A solid-state laser system with short pulse width, including an oscillator and an amplifier, was implemented. In the oscillator a classical E-O Q-switch method was used. The maximal output frequency is 20 Hz. In-depth discussion and analysis were focused on the phenomena that the laser beam with a quite high energy was reflected from the side of polarizer. And the cause of this phenomena was pointed out. It has been discussed that how to make use of this phenomena to guide the debugging of this kind of laser.