The invention discloses a viterbi demodulation system aiming at octal continuous phase frequency shift keying, and mainly solves the problems of high implementation complexity and difficulty in wide application in practice of a continuous phase modulation signal demodulator. The viterbi demodulation system comprises a current path measurement calculation module, a comparison selection module, temporary storage modules and a backtracking module. The current path measurement calculation module calculates out a current path measured value according to a received input signal, and inputs a calculation result into the comparison selection module; a maximum value is selected and fed into an accumulated distance temporary storage module, and a forward input corresponding to the maximum value is fed into a forward input temporary storage module; the steps above are circularly executed until backtracking conditions are met; data of the temporary storage modules is fed back to the backtracking module, and a final demodulation result is backtracked and output so as to complete viterbi demodulation. The viterbi demodulation system disclosed by the invention has the advantages of high information rate, real-time flow demodulation, low resource utilization rate and the like, and can be applied to an actual high-information-rate communication system.