In order to solve the problem of the worse decoding performance of the successive cancellation (SC) decoding algorithm under the medium/short code lengths, an improved successive cancellation list flip (SCLF) decoding algorithm is proposed by adding the path list and bit-flipping method on the basis of the SC decoding algorithm. The algorithm uses the bit-flipping to build the most unreliable information bit sets called as the flipping set (FS), and a new measurement criterion is proposed to reduce the range of the FS and improve the accuracy of the FS. The simulation results show that the proposed SCLF decoding algorithm can greatly improve the block error rate (BLER) with the increase of the signal-to-noise ratio (SNR). The gain of the SCLF (N=256, L=8) decoding algorithm is 0.55dB higher than that of the SC (N=256) decoding algorithm at BLER=10-3, the gain of the SCLF (N=256, L=8) decoding algorithm is 0.22dB higher than that of the CA-SCL (N=256, L=8) decoding algorithm at BLER=10-4, and the gain of the SCLF (N=256, L=16) decoding algorithm is 0.17dB higher than that of the CA-SCL (N=256, L=16) decoding algorithm at BLER=10-5.