Aimed at the Low-angle Height Finding problem under multi-path environment, a novel low angle height finding algorithm at sub-array level is proposed. First, the whole array was divided into three equal sub-arrays. Then, the orthogonal vector of covariance matrix at sub-array level was calculated accurately, not by Eigen Decomposition. Next, the angle spectrum was presented, whose peak just accords with the DOA of target. Finally, the complex reflection coefficient was estimated after the estimated DOA. How this algorithm relies on the SNR, the target’s elevation and complex reflection coefficient has been explained by simulations. Its efficiency was verified by outdoor data obtained by VHF band radar. The elevation angle error is 1.19 percent of beam width of array. This algorithm is independent on the unknown complex reflection coefficient, and the computation is lowered greatly. It can be applied in ship borne radar and VHF band 3-coordinate radar.