Background The Risk Adjustment in Congenital Heart Surgery-1 method（RACHS-1） and the Aristotle Complexity Score are in wide use throughout the world and have been shown to correlate reasonably well with cardiac surgery outcome. The Aristotle complexity score include two scores: the Aristotle Basic Complexity (ABC) score and the Aristotle comprehensive complexity（ACC） score. Objective To compare the two scores application and their advantages. Content RACHS-1 was a better predictor than ABC score with regard to the ability to predict mortality and morbidity. While ACC was a better predictor than RACHS-1. In order to achieve similar performance, RACHS-1 need to be further adjusted on age, prematurity, and major extracardiac abnormalities. Trend Efforts are taken to refine the two systems.They may eventually unify and become one.