Blind recognition of convolutional codes is widely used in the fields of information interception, intelligent mobile communication and multicast communication. In order to solve the problem of fast recognition of convolutional codes, the classical Euclidean algorithm is improved, and a method for blind recognition of convolutional codes based on improved Euclidean algorithm is proposed. Code rate is searched first, the check polynomial of convolutional codes is solved through iterative process, and the convolutional codes can be identified quickly. Validity of the algorithm is verified by the simulation results, and computational load is less than the algorithms in the literature reviewed.