Abstract: The automotive lighting assembly line is composed of equipments with different functions, as a critical performance index of equipment, accuracy is the guarantee for the yield of lighting. Taking the pallet jacking mechanism of the equipment as an example, with the help of tolerance analysis and calculation of assembly dimensional chain to determin the theoretical assembly accuracy. Then using precise instruments to measure the height value of each pallet at multiple ponits and calculate the equipment accuracy index according to the measured value and theoretical value, to ensure that the equipment meets the design accuracy requirements and the factory acceptance conditions.