Abstract: The modulated signal in conventional frequency hopping (FH) system is vulnerable to jammings. In this paper, a novel FH system, the multi-sequence frequency hopping (MSFH) was introduced. In MSFH, a bits block selected a hopping pattern from a bunch of orthogonal hopping patterns, and a carrier at the current frequency of this pattern was transmitted directly without any modulation. Compared with the differential frequency hopping (DFH) system, the frequency used in MSFH was constrained more tightly not only by the data transmitted, but also by the hopping patterns. By this term a narrow band receiver was applicable, so the structure of the system could be simpler and reject the out-band jamming more efficiently. Its BER performance over AWGN channel was examined explicitly with partial band jamming and briefly with follower jamming. Calculation and simulation indicates that, MSFH is almost not influenced by the follower jamming. When the BER is under the worst-case partial band jamming, MSFH requires signal-to-jamming ratio (SJR) of 1.5dB less than the conventional FH and 2.5dB less than the DFH symbol-by-symbol (SBS) detector.