The purpose of this study was to explore learning effects of using multimedia computer games in applied language curriculum for elementary students with mental retardation. A multiple-probe design across subjects was used. The independent variable was using multimedia computer games in applied language curriculum, the dependent variable was students' performance on vocabulary learning. The results of this study were: The teaching strategy to learning effects of all subjects showed significantly immediate effect; but the sustained effect of three subjects was different. According to the aforementioned findings and application of this study, instruction guidance and further researches were recommended.