There is the advantage of continuity in organic structure and mechanical property for functionally gradient materials (FGMs), but it is unable to be used in the mould industry for the difficulty of the second machining up to now. In this study, a novel technology of FGM mould with fine veins fabricated by plasma spraying has been developed, which can easily realize the integration of FGM forming and deep machining of the mould. According to applied characteristic of plastic injection mould, WC-12%Co/NiCrAl powders are selected and the reasonable FGM coating has been prepared. Spraying processes have been investigated, such as fabrication of spray mould with fine veins, FGM forming, backing and demoulding, etc. At the same time, the metallography, porosity and microhardness of the spraying layer have been analyzed. The results show that the service performance of the FGM mould is much more excellent than that of the traditional mould, and the life span can also be greatly improved. The research will have a significant influence on the material development in the mould industry.