The image of underwater laser imaging system ;UWLIS normally has poor contrast and high noise.To detect edges under this circumstance,two algorithms for improving anti-noise performance of Hough transform are designed.One is by adding the additional information of the direction of edge points,another by checking the connetivity between the edge points.The experiment of the mine-like object recognition with two algorithms described above is given.This result shows that the improved algorithms are evidently superior to the conventional algorithms.