Parameters of BCC/RCG-WG for daily precipitation simulation at 672 stations in China are calculated with historic daily precipitation data from 1951 to 1978 and from 1979 to 2007 respectively. Two sets of four parameters for the two periods are compared to review the impact of climate change on the parameters. The results show that transition probabilities from dry to wet and from wet to wet in most parts of China have a decreasing trend except parts of western China. The decreasing range of P(WW) in most parts of China are less than that of P(WD). Shape parameter ALPHA of GAMMA distribution of daily precipitation in most parts of China has a slightly increasing trend except parts of western Northwest China. Scale parameter BETA of GAMMA distribution of daily precipitation in most China, especially in parts of western Northwest China, has an obviously increasing trend. Compared with BETA, the changes of ALPHA are generally smaller (within 6%) in most China. Changes of parameters of daily precipitation simulation in each month and season are also analyzed, which shows a regional and seasonal difference.