Abstract: On the basis of describing real-time obstacle detection algorithm, coordinate transformation using range image of laser range sensor in ALV, this paper mainly studies the influence of ambiguity interval of laser range sensor and the errors of center angle of laser vertical scanning scope and the ALV attitude angles upon the results of obstacle detection. We present a method, in which we first reckon the value of center angle using range image of horizontal plane without obstacle, then obtain the value of center angle according to least square fitting. In addition, technique is also presented to minimize error of obstacle detection for thresholding elevation, which use different datum elevation in different row of elevation image.