Abstract: Integrated small pressurized water reactors are with compact layout of equipment and with narrow space,and its maintenance accessibility has always been a challenge in the design and operation period.But there is no qualitative method for the effective evaluation of the maintenance accessibility.Products with good maintainability not only ensure the reliability,but also ensure the minimum maintenance required resources（such as time,manpower,material and costs）,and thus ensure the optimized maintenance economy under the premise of safe maintenance.Based on the design features of the integrated small pressurized water reactors,this paper analyzes the key equipment maintenance requirements,and presents the maintenance accessibility evaluation index.