Improving the ability to solve mathematical word problems is one of the most critical issues facing students with developmental disabilities, because it is directly related to their independent living skills. The purpose of this study was to propose a teaching model that implements augmented reality (AR) and video modeling (VM), and to validate its effectiveness, including its immediate, maintenance, and generalization effects on improving the percent accuracy of solving mathematical word problems. The research design of this study adopted single-case multiple probe across students experimental design. The independent variable of this study was the VM with AR teaching model, and the dependent variable was the percent accuracy of the test subjects in solving mathematical word problems. All three test subjects showed an immediate effect, with two showing maintenance and generalization effects. This VM with AR teaching model provides an alternate way for classroom teachers when teach students with developmental disabilities to solve mathematical word problems. This teaching model allows students with developmental disabilities to improve their mathematical word-problem solving skills.