Abstract: In order to improve the performance of the VHF radar in low angle tracking and reduce the affect of the beam split,the oblique planar array is used in VHF radar systems actually.However,the oblique array is always approximated by the vertical array in practice.Under the approximation,the measurement of altitude diversity is applied.As a result,the wave distance,which is the function of azimuth and elevation in fact,is related to the elevation angle only.This paper proposes the altitude measurement based on the oblique array in VHF radar by the method of altitude diversity.The new method is close to the practical situation by the precision model.The simulation shows the validity of the new method.