The invention discloses a PTC thermistor, comprising: silver-plated copper powder, carbon fiber, wollastonite, mica powder, aluminum nitride, epoxidized triglyceride, linear low-density polyethylene and dicumyl peroxide, wherein components in the PTC thermistor have the parts by weight of: 31-40 parts of silver-plated copper powder, 9-18 parts of carbon fiber, 5-12 parts of wollastonite, 4-10 parts of mica powder, 17-26 parts of aluminum nitride, 11-19 parts of epoxidized triglyceride, 20-29 parts of linear low density polyethylene, and 4-12 parts of dicumyl peroxide. In the above manner, thePTC thermistor provided by the invention has low room temperature resistivity, long-term flow-through stability, high PTC strength, and high PTC stability.