Influence of polarization effect on current across GaN/AlNresonant tunneling diode (RTD) is simulated by self-consistent calculations ofSchrödinger and Poisson equations. When taking into account polarization chargesat the heterointerface, the band diagram and electronic properties of RTD areobviously changed. As a result, the current-voltage characteristics showsasymmetrical phenomenon. As the polarization effect is enhanced, the resonancepeak is shifted accordingly and even disappears.