The infants who cannot be breastfeed need to obtain energy and nutrition from other sources, such as formula. In this study, a human milk fat substitute (HMFS) rich in structured triglycerides (STG) and with a variety of fatty acids was prepared by one-step transesterification reaction. The optimum conditions for the lipase-catalyzed transesterification between basa catfish oil solid fraction, Cinnamomum camphora seed kernel oil, linseed oil, microbial oil and algae oil were studied and the in vitro digestibility of the constructed HMFS was investigated. Under the optimal conditions, the obtained HMFS contained 58.86% STG and 39.73% sn-2 palmitic acid (PA). Fatty acid composition analysis showed that HMFS was composed of capric acid (Ca), lauric acid (La), oleic acid (O), linoleic acid (L), linolenic acid (Ln), arachidonic acid (ARA) and docosahexaenoic acid (DHA). LC-MS/MS analysis found that 142 new triglycerides were generated, such as Ca-P-ARA, Ca-P-Ln, La-P-ARA, La-P-L and P-O-ARA. Moreover, compared with physical mixture (PM), HMFS had better melting and crystallization temperature and the fatty acid release rate of HMFS was significantly improved. These results suggested that HMFS may have a great application in infant food as a nutritional ingredient.