High polymer and stainless steel are commonly used for key friction pairs of hydraulic piston pump. In order to compare wear properties of Carbon Fiber (CF) reinforced Polyimide (PI) and Polyetheretherketone (PEEK) polymers, PI and PEEK with 10% and 30%CF are respectively prepared. Friction coefficient and wear rate were obtained through friction and wear test sliding against AISI 630 steel under water lubrication, and the wear mechanism was analyzed by means of wear morphology. It is shown that CF reinforced PEEK exhibits better friction stability and wear resistance property than CF reinforced PI. Friction and wear properties of 30%CF reinforced PI is better than 10%CF reinforced PI, while 10%CF reinforced PEEK is better than 30%CF reinforced PEEK. With CF content increasing from 10% to 30%, friction damage of their dual surface ie. AISI 630 is aggravated. Under seawater lubrication, wear mechanism of CF reinforced polymer sliding against AISI 630 is abrasive wear, and abrasive wear of PEEK/AISI 630 is slight, while abrasive wear of PI/AISI 630 is more serious. The above results can provide material selection reference for friction pairs in hydraulic piston pump.