Different heating treatments with the variation of heating rates, holding temperatures and holding time were used to simulate the LTPS procedure. The experimental results show that the reheating shrinkage rates of glass substrates are rarely changed with increasing the heating rate, but strongly enhanced by raising the holding temperature and time, which shows that the reheating shrinkage of glass is closely related to heat treatment and structural relaxation. The production process of glass is critical to the reheating shrinkage of glass.