The properties of the bound magnetopolaron in a triangular quantum well were investigated within Lee-Low-Pines(LLP) variational
method. At different Coulomb bound potentials, the ground state energy and the ground state binding energy were obtained as functions of the cyclotron resonance frequency of magnetic field and the electron areal density. The results showed that the ground state energy was found to increase with the electron areal density and the cyclotron resonance frequency of the magnetic field, whereas the ground state binding energy was found to decrease with them.