Abstract: Basic principle of amplitude-comparison in height finding is discussed,and various factors affecting the accuracy of amplitude-comparison in height finding are analyzed.Errorness quantity caused by these factors is calculated.A single correction method is provided,that is,based on the height finding value of the primary radar and the height finding value of the secondary radar,the paper calculates the adjustment quantity of the antenna beam direction,micro-adjusts the arrary of antenna,and so that it improves the accuracy of height finding.Because the adjustment of antenna beam direction is in a very small range,so the effection on antenna sidelobe and beamwidth can be omitted,that is to say,it will not make any effection on other performances of the radar system.