A method of differential frequency hopping which can overcame the disadvantage of data rate and synchronization in traditional frequency hopping communication is used in underwater acoustic communication regarding the safety and reliability. Based on the shortcoming of the CHESS radio G function, a system model is proposed and a new designing method for G function is presented based on m sequence. New G functionpsilas frequency hopping pattern is analyzed and tested ,The results showed that frequency hopping sequence produced by new G function has good uniformity and randomicity which has a better performance in anti-jaming and antimultipath and has a good application prospect for underwater security communication.