A Syndrome-assisted list decoding algorithm for BCH codes of B1I navigation signal in China Beidou Satellite navigation system is proposed. First, error pattern lists are built based on syndrome and Hamming weight. Then, the syndrome of hard-decision sequence is used to select the list for decoding. Finally, the optimal error pattern is found for decoding by using correlation function difference metric. The results of simulation show that, the difference of SNR between proposed algorithm and Maximum-Likelihood (ML) decoding is less than 0.08 dB at BER of10-5 which illustrates that the syndrome-assisted list decoding algorithm is a near optimal decoding algorithm for BCH codes of Beidou B1I signal. Additionally, the new algorithm is linear complexity and can be parallel implemented.