The invention relates to a quality detection and supervision method and system. The method comprises the steps of classifying the common materials used for power network construction and operation according to the importance degree; establishing a variety of different forms of material quality supervision, and different levels of material quality supervision methods and sequences, wherein the material quality supervision forms include supplier inspection, sample testing, arrival inspection, periodic sampling, special sampling. The invention is conducive to comprehensive and high-efficient supervision and management, and ensures the intrinsic safety of power grid materials and the stable operation of the power grid.