In this study, the developed microcomputer-based experiment was applied to examine its effectiveness to overcome the existing problems of experiments on photosynthesis and respiration of the plants. The study targeted 144 (72 male and 72 female) 8th graders who were divided into the experimental and the control groups. The experiments on photosynthesis and respiration of the plants were conducted using both the improved microcomputer-based experiment method and the existing experiment method. As a result, the improved microcomputer-based experiment showed a statistically significant difference from the existing methods in terms of the accuracy of the experimental results, and the ease with which data analysis and data transformation could be performed by the students (p<.05): further, it shortens the experiment time. These results could indicate that improved microcomputer-based experiment on photosynthesis and respiration of the plants would expected to be a good solution for the problems with the existing experiments on photosynthesis and respiration of the plants.