Functional maintenance of terminally differentiated cells outside the in vivo microenvironment has proved challenging. Current strategies that manipulate cell-cell or cell-matrix connections are difficult to constitute complex regulatory networks for cell function maintenance. Small molecules are easily combined for flexible spatiotemporal modulations, theoretically favorable for synergetic regulation of cell-innate signaling pathways to maintain cell function in vitro. Here, we developed small-molecule cocktails enabling robust maintenance of primary human hepatocytes (PHHs) longer than four weeks, with gene expression profiles, resembling those of freshly isolated PHHs; and prolong-cultured PHHs, for the first time, could maintain drug-metabolizing activities of enzymes accounting for over 80% of drug-oxidation and support hepatitis B virus infection in vitro for over one month. Our study demonstrates that this chemical approach effectively maintains terminally differentiated hepatocytes in vitro, which could be extended to various cell types. Overall design: Total of 29 samples were analyzed, which included primary human hepatocytes (PHHs) cultured in different condition in vitro. To figure out how terminally differentiated cells rapidly lose their function in vitro, two PHHs samples were compared, which included 24h-Cultured hepatocytes and fresh primary human hepatocytes (F-PHHs) [GSM2893923 and GSM2893924]. For comparison of global gene expression of primary human hepatocytes (PHHs) maintained with small molecules or sandwich culture for different time periods, sample3-29 were analyzed [GSM2893935 - GSM2893963][GSM3629857-GSM3629862].