Many elementary school students have misconception related to dissolution and solution. Moreover, they usually fail to apply the results of the experiments in their science classes to their everyday life, and also have low science achievement. Therefore, they are not interested in science, and sometimes some of them are even afraid of it. The purposes of this study is to investigate the effects of concept mapping activity on science achievement and attitude. In addition, this study also aims at presenting the teaching and learning method of utilizing concept maps in order to have the students form correct concepts. The subjects were classified into two groups one group is composed of thirty-seven students (experimental group) who were participated in concept mapping activity, and the other is composed of thirty-eight students (comparison group) who were participated in the traditional teaching method. The major findings of this study are as follows: First, the concept mapping activity has a positive effect on improving students＇ science achievement. Second, the classes using concept maps have a good influence on forming students＇ science attitude. Third, the concept mapping activity is more effective in improving science achievement of mid and low level students. In conclusion, the loaming by concept mapping activity positively influence students＇ science achievement and attitude. Particularly for the students in mid and high levels, the effect is more remarkable.