In order to solve the problem that the real-time performance of machine vision detection is insufficient, the line of sight is short, and the environmental adaptability is poor, which cannot meet the requirements of all-weather and multi environment operation of railway, a method of object detection in railway direct rail environment based on microwave radar is proposed. Firstly, the measurement characteristics of radar are calibrated by off-line experiment, and the error correction function of radar is obtained by data processing. Then, the railway safety gauge standard, radar measurement parameters and radar lateral measurement error are integrated to construct the gauge area under the radar coordinate system in real time, and the object after error correction is judged to be within the gauge. At the same time, the moving targets in the radar detection range are filtered and tracked. The real test results show that the radar has good detection performance, high real-time performance and good environmental applicability.