Abstract: Originally developed for HF communications in military applications, DFH systems possess high spectral efficiency features. As a combination of frequency hopping, modulation and coding techniques with G function, DFH technology can not only effectively enhance the transmission rate of the HF communication system but also effectively combat multipath fading and interference which restricts HF communication development. To improve the DFH systems flexibility and capacity, in this paper, we propose a wideband MFSK/DFH system model. Unlike in traditional DFH system where the anti-jamming performance is determined by the number of available frequency choices, in MFSK/DFH, a G function constructing method based on state trellis diagram was presented which coding gain and system capacity can be improved by increasing the coding complexity. The theoretical analysis and simulation results of symbol error rate for the FFT based receiver in AWGN with partial-band noise jamming are also given. The results of a more detailed analysis show that the proposed method improves anti-jamming performance by increasing the coding complexity. The implementation is simple and has some practical value.