The traditional underwater pump is suitable for long-term transportation of any concentration of strong acid, alkali, salt, strong oxidant and other corrosive media. The new type of liquid pump is suitable for conveying light, flammable and explosive articles, with the characteristics of maintenance-free, explosion-proof and low energy consumption. The shell, pipe, outlet pipe and flow parts of the traditional liquid pump are all made of plastic alloy (PTFE,FEP) pressed and sintered. All parts of the main pump are placed in the liquid, with strong corrosion resistance, high mechanical strength, no oxidation, non-toxic decomposition characteristics.