A blind recognition method of cyclic codes is proposed. Under the condition of having known the starting point of the code words，code weight distribution of cyclic codes is analyzed，and code length is recognized based on code weight distribution probability variance. According to the statistical results of code weight distribution, the appropriate code words are chosen，then the common factor of code polynomial after cyclic shift is obtained. Finally, the generated polynomial is recognized by setting a rational judgment relation，thus the blind recognition of cyclic codes is completed. The simulation experiments show that the method has better recognition effect for cyclic codes with BER of 10-2.