The cyclostationary-based spectrum sensing algorithm in OFDM systems is studied in this paper. An embedded pilot-based cyclostationary detection algorithm is proposed and the simulation are carried out under different channel conditions which show that this algorithm does not depend on the length of CP and has better overall performance in low SNR and fading channel environments than others. The performance loss caused by the unrelated combination can be compensated by extending the sensing time under the fading channels. In addition, the algorithm is more practical when the values of pilots are pseudo-randomly coded for a practical OFDM system.