Abstract: Based on the anti-jamming performance study of uncoded differential frequency hopping(DFH)systems, this paper introduces low-density parity-check(LDPC)codes to the DFH systems and investigates the improvements against partial-band jamming.When exact jammer state information(JSI)is available, irregular LDPC codes are optimized with respect to different jamming factors.The cycle-free asymptotic ensemble average bit error rate(BER)is given and the anti-jamming performance of optimized LDPC codes and regular LDPC codes are simulated.Results show that when exact JSI is available, the anti-jamming performance of optimized LDPC coded DFH systems is obviously superior to that of the regular LDPC coded and uncoded DFH systems.When JSI is unavailable, a joint JSI estimation and decoding algorithm is proposed.Simulation results show that this algorithm provides robust anti-jamming performance even without JSI.