The SCFs of some noise, interfering and LPI radar signals are illustrated, the performance advantages of using SCF to detect LPI signals in noise or interference environments are analyzed. The SCF is also compared with Wigner-Ville distribution, dechirping and ambiguity, the equality among them is found. Moreover, several SCF algorithms are evaluated. It can be evidenced that the SCF is an efficient method of detection LPI signals, which has the good performance of resistance against the interference and the capability of realizing real time detection.