The purpose of this study was to investigate the mediating effect of grades, positions, and match results inthe causal relationships between achievement-goal orientation and sport flow among middle and highschool soccer players. The total data of 448 copies were collected from middle and high school soccerteams while 405 copies were accepted for final analysis without 43, and multi-group confirmatory factoranalysis was conducted to the data. The result of latent mean analysis showed that middle school playershad significantly higher mean in sense of control of sport flow and transformation of time, and defendersshowed significantly higher than offenders in ego orientation and transformation of time, while winninggroup achieved significantly higher than losing group in all factors except ecstasy. Also multi-groupanalysis showed that achievement-goal orientation had significant effect on sport flow in middle and highschool players, and middle school players had more powerful effect than high school players. Meanwhile,the achievement-goal orientation affected significantly on sport flow in offenders and defenders, and egoorientation of offenders affects on sport flow. task orientation of winning and losing groups had significanteffect on sport flow, and ego orientation of winning group showed significant effect on sport flow.