In our previous work, our grouping mechanism based on edX online forum, which aims to help teachers form learning groups in SPOC context. We proposed the interaction as the main criterion and heterogeneous academic results as the supportive to do grouping. In the past experiment, we compared our method to student grouping by themselves, our method is better in learning performance but satisfactions is worse. In this paper, we continue the previous work, and make some changes for the experiment content, in order to carry out a second experiment. Moreover, in this paper a more in-depth analysis and comparison of experimental results twice. In the second experiment, we found that the results of the post-test is worse than the first experiment. We believe that the main reason may be that the participation of the online discussion board is reduced, leading to interactive information can be obtained also reduced. Eventually leading to less effective of our method. But the experimental group grade still higher than the control group and have the same satisfaction about grouping result in the second experiment.