Abstract: In order to study the radius deviation compensation method for the boundary position of the centrifugal shaped reflector surface of bifocal reflector，the trend of melt movement and the deviation of boundary position in the centrifugal casting of bifocal reflector are studied using simulation analysis and analogy experimental method. The spin casting forming process is simulated and analyzed, and studied by way of analogy experiment. The compensation calculation was conducted for the radius deviation of boundary between the inner and outer reflecting surfaces. The simulated results of the forming process of the bifocal reflector were compared with the results of the forming experiment. The results show that the maximum surface shape errors are 6.5 μm and 7.2 μm，and the radius deviations of boundary positions of inner and outer reflectors are 5.2 μm and 7.1 μm，which proves that the numerical simulation method can predict the trend of melt movement during the forming process of bifocal reflector. Different radii are set for cylindrical thermal insulating wall. The simulations are carried out with three different bifocal reflectors, which were formed at 50 r/min for the outer ring reflecting surface and 90 r/min, 100 r/min and 110 r/min for the inner ring reflecting surface. When the position radii of the thermal insulating wall is set 31.08 mm，30.7 mm and 30.39 mm，the boundary position radius deviations of reflector surface are reduced from 4.358 mm，4.264 mm and 4.199 mm to 2.15 μm，2.40 μm and 5.30 μm，respectively. The deviations radii are micron-sized. So it is verified that the boundary position radius of reflector surface can be compensated by changing the position radius of the thermal insulating wall during the spin casting.

Key words: bifocalreflector, spincasting, reflectorboundaryposition, analogyexperiment, errorcompensation