Aiming at the problem of low impact toughness of the impregnated diamond bit matrix, a method of adding stainless steel fiber net to the carcass to improve the impact toughness of the matrix is proposed. The impact toughness of matrix was tested at different combinations of the three variables: the placement, mesh and number of layers of the fiber net. It was obtained through experiments: (1)stainless steel fiber mesh can effectively improve the impact toughness of the matrix, and the X-axis placement position is better; (2)when the mesh number of the fiber web is the same, the impact toughness of the matrix decreases as the number of fiber mesh layers increases; (3)in the case of the same number of fiber net layers, the impact toughness of the matrix increases first and then decreases with the increase of the number of fiber net layers. With a single layer of 30 mesh net added, the impact toughness of the carcass reaches a maximum. Through the electron microscopy of the impact fracture and the mechanical analysis of the fiber net, the reasons for this law are explained, and the method of further optimizing the impact toughness of the matrix is proposed.