The magnetic field integral equation (MFIE) is solved by Coiflets for rough surface scattering. The vanishing moments of Coiflets provide one‐point quadrature, which slashes the matrix filling effort from O(N2) to O(N), and consequently reduces the complexity scaling in between O(N) and O(Nlog N) for problems with unknowns up to 106. The bi‐conjugate solver converges very fast owing to the well‐posedness of the MFIE. The resulting impedance matrix is further sparsified by the matrix‐formed standard fast wavelet transform. By properly selecting multiresolution levels of the total transformation matrix, the solution precision can be enhanced while matrix sparsity and memory consumption have not been noticeably sacrificed. Numerical results are compared with the Rao‐Wilton‐Glisson multilevel fast multipole algorithm (RWG‐MLFMA) based commercial software FEKO, and good agreement is observed.