The present application relates to a high mechanical strength polymer thin film. The high mechanical strength polymer thin film comprises, by mass percentage, 95%-99% of polyester and 1%-5% of an auxiliary agent. The number average molecular weight of the polyester is 13000 Da to 20000 Da. The molecular number of the polyester with the molecular weight smaller than 5000 Da accounts for 0.5%-5% of the total molecular number of the polyester. A molecular weight distribution index of the polyester is 1.6-2.4.