Current recognition methods for convolutional codes are only applicable to a specific code rate, and fault tolerant performance needs to be improved as well. To solve this problem, a parameter method based on parameter traversal and improved threshold WalshHadamard transform (WHT) is proposed. According to the coding structure, F(2) equations for check polynomials are established in both cases of nonsystematic and systematic codes, with binary hypothesis being established. By traversing the possible coding parameters and solving the equations via WHT, the correct check polynomials are determined through threshold decision, while the threshold is improved based on maximum and minimum criterion to enhance robustness at the same time. Finally, generator polynomials are calculated on the basis of orthogonal relationship between check matrix and generator matrix. Simulations verify the applicability of the proposed method, which has a better error resilient performance compared with current recognition methods.