The characteristics of optical code division multiple access（OCDMA） and convolutional codes were introduced.Based on the tunnel model of OCDMA with its multiple access interference（MAI）

and according to its characteristics

a novel decoding of convolutional codes was proposed.Compared with the primary decoding

viterbi algorithm

the error robustness and rate of proposed decoding was studied.The analysis shows that this novel decoding can improve the error robustness capability of convolutional codes.It also can reduce the procedures in picking up the trellis when decreasing the decoding complexity and raising the decoding rate.