The bit-error-rate (BER) performance of an LDPC decoding algorithm will be seriously degraded when the algorithm is realized with fixed-point implementation in practical applications, due to the introduced quantization errors and rounding errors. To remedy the problem, this paper proposes an improved min-sum algorithm (MSA), called CMVP algorithm. It achieves better performances than the popular min-sum algorithm (MSA), under the condition of the same fixed-point precision. Besides, the hardware overhead of the new algorithm over conventional MSA is small. On the other hand, under the condition of comparable performances, MSA algorithm needs a higher fixed-point precision and hardware costs than the new CMVP algorithm, according to the simulations and hardware synthesis results. The new algorithm also works well in a wide range of code rates and code lengths.