The aim of this study is the effect of multimedia education on understanding the concept and solving the mathematical problem of fifth grade students. The method used is a quasi-experimental type with pre-test and post-test and two experimental and control groups. The target population of this study was the fifth grade male students of Qarchak city who were studying in the academic year of 98-99 and the selected samples were randomly assigned to 60 students in two control groups (30) and 30 people were tested. The research tools were used for multimedia training of Aria e-bag software and for understanding the concept (spatial, spatial and temporal) and solving the mathematical problem that the researcher had asked. The validity of this test was 0.744 through Cronbach's alpha and its validity was confirmed according to experts. Data analysis collected in the study was performed using SPSS software and using descriptive statistical methods of mean indices, standard deviation and in the inferential statistics section, covariance analysis method was used. The results show that there is a significant difference between the mean of post-test scores of the two control and experimental groups in the dependent variable of understanding the concept and solving the mathematical problem. This confirms the effective role of multimedia teaching on better understanding of mathematical concepts (spatial understanding, spatial understanding and temporal understanding) and solving math problems of fifth grade students.