Measurement of solid rocket nozzle thrust line is one of a key technique in the field of spacecraft precise installation and is a representative application of rotation axis line extraction of rotational symmetric object. Given that the existing methods have the problems such as nonobjective, poor reliability and low adaptability, an automatic solution for rotation axis extraction from 3D scanned high density of point cloud data was proposed, in which all the surface points and their normal vectors were utilized as constraints. Firstly, the normal vector of each point in point cloud was calculated and unreliable points were eliminated according to the standard deviation value of local planar fitting for normal vector calculation. Then, the initial value of rotation axis was achieved through planar and spherical fitting of reference points which had same latitude with the randomly selected reliable seed point. Finally, refinement result of rotation axis was calculated by solving the objective function listed based on the relationship between normal vectors of each reliable point and the rotation axis. The test experiments were performed, and the accuracy and precision of the method were verified by simulated and measured data. The experimental results indicate that the deflection degree is under 0.003° and the transverse distance is under 0.02 mm, which satisfies the requirements of rotation axis extraction of rotational symmetric object.