Objective To explore the information of rice lysophosphatidic acid acyltransferases (LPAT) gene family, and analyze the bioinformatics characteristics and its role in rice grain oil synthesis. Method Through bioinformatics analysis, the gene structure, phylogenetic tree, tissue expression profiles, hormone and stress expression profiles of OsLPAT gene family were analyzed. The roles of OsLPAT family members in rice grain oil synthesis were analyzed by comparative metabolomics and transcriptome methods. Result The rice genome contain five LPAT genes, named OsLPAT1-OsLPAT5. Except OsLPAT1, other members all contain 4-6 exons, and each member contains the acyltransferase C-terminal (PF01553) domain. The evolutionary analysis showed that the LPAT genes were relatively conservative in monocotyledon. OsLPAT2 was sensitive to various stress conditions and hormones. The expressions of OsLPAT3 and OsLPAT5 were strongly induced by abscisic acid (ABA), while OLPAT4 was specifically induced by osmotic stress. Comparative metabolomics and transcriptome analysis showed that each member of the OsLPAT family played roles in different stages of grain development, thereby promoting the synthesis of oil triacylglycerol (TAG). Conclusion There are five LPAT genes in rice genome, whose expression are induced by different hormones and may play roles in the hormone response process of rice. The members of this family are involved in the synthesis of phosphatidic acid (PA), the oil precursor in grains at different development stages, thus positively regulating the oil synthesis in rice grains.