Normal>Based on systematic field observation of veins, the authors divided the veins in the Tongchang porphyry copper deposit into four types: A, B, D and H, which have recorded the evolution of ore fluids. A statistical analysis of the thickness distribution of veins in the Tongchang porphyry copper deposit indicates that vein thickness data conform to the power-law distribution whereas the spatial distribution of veins follows a negative exponential law or a law between the negative exponential and log-normal. The fractal dimension D relative to the linkage of vein systems reflects the mineralization rate. The veins located in the clustering center as the function of channel ways for ore fluids are thicker and control the development of vein systems.