In this study, functional modified montmorillonite (MMT-PMMA) was obtained through polymethyl methacrylate (PMMA) intercalation modified montmorillonite (MMT). After MMT-PMMA preparation slurry was coated on the PP microporous membrane, Then immersed the PP microporous membrane in a tannic acid (TA) solution to obtain a modified microporous membrane (PP/MMT-PMMA/TA) with high electrolyte wettability and high heat resistance. The contact angle test result shows: After modification of the PP microporous membrane, the electrolyte contact angle decreased from 47° to 0°, and the electrolyte absorption rate increased from 97.5% of the PP membrane to 136.6%, proving that the PP/MMT-PMMA/TA microporous membrane has a good Electrolyte affinity. The heat resistance of the microporous membrane was tested at different temperatures for 30 min. The results show that the heat resistance of the PP/MMT-PMMA/TA microporous membrane is significantly improved compared to the PP microporous membrane before modification. The battery performance test results show that the first charge and discharge capacity (60.0 mAh/g) of the battery assembled by the PP/MMT-PMMA/TA microporous membrane is 45% higher than that of the PP microporous membrane (41.3 mAh/g) before modification. And the rate performance is better.