In the band theory,first-principles calculations,the tight-binding method and the effective k·p model are usually employed to investigate electronic structures of condensed matters.The effective k·p model has a compact form with a clear physical picture,and first-principles calculations can give more accurate results.Nowadays,it has been widely recognized to combine the k·p model and first-principles calculations to explore topological materials.However,the traditional method to derive the k·p Hamiltonian is complicated and time-consuming by hand.We independently developed a programmable algorithm to construct effective k·p Hamiltonians for condensed matters.Symmetries and orbitals are used as the input information to produce the one-/two-/three-dimensional k·p Hamiltonian in our method,and the open-source code can be directly downloaded online.At last,we also demonstrated the application to MnBi2Te4-family magnetic topological materials.