In this study, we researched that in situ heating transmission electron microscope (TEM) experiments were carried out to research heteroepitaxial growth of 3C-SiC on Si nanomembrane (NM). We developed a specific Si NM to observe growth of very thin and uniform 3C-SiC in real-time. We demonstrated structure of 3C-SiC on Si NM by using several TEM images and simulation results. In addition, we focused to occur the heteroepitaxial growth at lower temperature, and studied how large scale 3C-SiC growth is possible. Based on these results, we proposed a new perspective on the problem about the growth mechanism for heteroepitaxial growth on Si NM through in situ heating TEM study.