Pistachio sorting technique research using impact acoustics is a method, which is to make pistachio vibrating and sounding when impacted, and get the connection between its signal features and structure characteristics through acoustics analyzing. Pistachio is considered as a nested ball , and analyses the whole process from the ground until the last moment of free vibration attenuation, and explains that the time domain and frequency domain characteristics of pistachio will perform different vibration characteristics based on the levels of opening. A new selecting method based on time-domain signal integrated logarithmic decrement is presented, and sorting effect is obvious.