Press light-leakage was a defect in the joint production of ADS TFT-LCD. In this paper, the causes of press light-leakage in 1 225 mm(55 in) product based on 8.5G factory are analyzed. It is found that the light-leakage of fixed position is caused by external stress deformation. At the same time, the influence of the pattern of sealant on glass, and the stress of glass before sealant cured are studied. The defect is effectively improved by changing the motion mode of turn-over, the light-leakage level dropped from the second leve 2(L2,the phenomenon of customers don't accept) to the first level(L1,the phenomenon of customers accept). In addition, the method is implemented for the first time, and provides an idea for solving lisht-leakage for other products.