The precipitation hardening stainless steel is used as the material of leadscrew in the screw-roller-nut type control rod drive mechanism in nuclear reactors. To improve poor tribological properties of the leadscrew, low-temperature plasma nitriding is commonly applied as a promising surface treatment technology. The study investigates the sliding wear behavior and model for low-temperature plasma nitrided precipitation hardening stainless steel in high temperature water. Low temperature plasma nitriding was carried out at 410 ℃ for 1 h. The wear and the general corrosion test were conducted at 280 °C/13 MPa water. The results show that the nitrided layer primarily consists of lamellar-structured γʹ-Fe4N. The nitrided layer undergoes oxidational wear. As the wear proceeds, the oxide film thickness increases; once it reaches a critical value, the film peels off, resulting in material loss. The effect of plastic strain on oxide film growth was analyzed by calculating its impact on grain boundaries and dislocation density. A preliminary predictive model for the wear volume of nitrided layer was constructed by the theory of oxidational wear. The study of the sliding wear behavior of low-temperature plasma nitrided precipitation hardening stainless steel in high temperature is crucial to guide the design of new materials in nuclear reactor applications. The proposed model offers a novel approach for predicting wear volume of material in high temperature water and provides theoretical guidance for assessing material degradation in other corrosive environments.