AbstractFree phytosterols (PS) and phytosterol esters (PSE) usually coexist in natural edible oils, which affect the crystallization behaviors of oil significantly. However, the phase behaviors of PS and PSE in oils and their roles on the crystallization behaviors of oil are still unclear. In this study, the isolation and dissolution behaviors of PS and PSE in medium chain triglyceride (MCT) were studied, and then their influences on the crystallization behaviors of MCT were clarified further. The results showed that when the mass ratio of PS:PSE was greater than 3:7 at the total amount of PS and PSE fixing 5 wt%, PS and PSE isolated to form a new crystal structure, which was different from PS spherical or PSE plate‐like crystal structure, in MCT. The new PS/PSE crystal structure had a larger surface area, and its melting point was between PS and PSE. It also showed the synergistic ability to promote the crystallization nucleation of MCT. When the total content of PS and PSE was 1 wt%, and the mass ratio of PS:PSE was 5:5, the crystallization peak temperature of PS/PSE/MCT was 12°C higher than that of virgin MCT, 2.5°C higher than that of PSE/MCT, and 10.3°C higher than that of PS/MCT.