Laser scanning ranging radar is an important tool for machines to perceive the surrounding environment and is widely used in the power, forestry, surveying and mapping industries. At present, the loading of oil and grain oil in our country generally adopts the way of manual loading. The loading arm is inserted into the tank of the tanker for refueling, and the loading operation is very frequent. In order to realize automatic control of grain and oil loading, radar is needed to assist the robot to locate the oil port of the tanker. In this paper, a 360-degree laser scanning ranging radar is used to collect characteristic data of oil hole of tanker for the first time in simulated environment. Cubic spline interpolation was used to smooth and correct the radar scan data. Based on the feature that the distance data of oil port will change rapidly, an edge feature recognition algorithm is proposed to screen and calculate the target point, and then convert it to cartesian coordinate point, which can be used as the positioning target of the robot unit of quantitative loading system. The experimental results show that the method can locate the center of the circle accurately and meet the requirement of feature recognition accuracy.