Abstract: Tomato locule is closely related to fruit size and shape, the more locule number, the bigger the fruit is, and then it is more likely to be malformation, which affects yield and quality of tomato directly. In order to find out tomato locule formation and regulation mechanism, the author summarized the regulatory relationship between tomato locule and environment, plant growth regulator, heredity and genes. Low night temperature and high nutrition level promote tomato locule formation, low light density decreases the number of locule, the irrigating amount and frequency also influence the locule formation. GA3, B-9, BA, TIBA promote the loucle formation, GA3 plays the most important role. 2,4-D inhibits the locule formation, IAA and NAA make the locule number with a downward trend. The genes that regulate locule formation include lc, WUS, fin, fab and CLV3, and there are two regulation pathways, WUS-lc pathway and fin/fab-CLV3 pathway, respectively.