<p>Within the framework of the effective mass approximation theory, linear combination operators are incorporated to describe the momentum and position coordinates of heavy holes. By employing variational techniques in conjunction with the unitary transformation method, the Rashba effect of polarons with heavy-hole characteristics in a triangular quantum well is systematically investigated. The functional relationship of the polaron effective mass is derived theoretically. Owing to the Rashba effect, the polaron effective mass undergoes splitting from its spin-degenerate (zero-spin) state, with the spin-split effective mass of the heavy-hole band exhibiting a negative value. Numerical computations of the polaron effective mass were performed for cases with and without phonon. The calculation results show that the polaron effective mass is an increasing function of the vibration frequency and the hole-phonon coupling strength. The spin-splitting magnitude increases with the increase of vibration frequency, hole-phonon coupling strength, and hole areal density, but decreases with the increase of velocity. Compared with the case without phonons, the polaron effective mass is larger when phonons are present.</p>