The error ellipsoid is introduced into the evaluation of point cloud precision analysis.The relationship between error ellipsoid and point covariance is studied emphatically.The scale factor used to describe point error ellipsoid is acquired according to the point probability of error ellipsoid corresponding to the different scale factors.The overlap of adjacent error ellipsoid is determined according to the relationship between the adjacent error ellipsoid and the scanning interval.The point cloud error ellipsoid is calculated in the case of intersection between the error ellipsoid.The average point error ellipsoid is acquired according to the point cloud error ellipsoid.The average point mean square error is calculated by using the relationship between error ellipsoid and point mean square error.The evaluation of point cloud precision is realized according to the error ellipsoid.