Abstract: In a serially concatenated CPM system with symbol-interleaving, there is a phenomenon that the system with better outer codes, otherwise, its iterative decoding system performance was worse. To mitigate this phenomenon, a novel symbol-interleaved SCCPM was investigated, which combined the features of the symbol-wise and bit-wise interleaving, the sequence of information bits per symbol was permutated optimization before mapped to a symbol. Compared symbol-wise interleaved SCCPM scheme, using the mentioned permutated optimization schemes, it can speed up the convergence rate of iterative decoding, while the performance of the outer code may also directly affect the symbol interleaving SCCPM system performance with ignored decoding delay.