Tetrahydrocurcumin (THC), one of the active metabolites of curcumin, possesses pharmacological activities similar to those of curcumin, such as hypoglycemic, hypolipidemic and antioxidant effects. However, poor water solubility of THC leads to an unfavorable absorption, which limits its application. The aim of this study was to improve the solubility of THC through cocrystallization. Five cocrystals of THC with L-proline (THC-L-PRO), D-proline (THC-D-PRO), DL-proline (THC-DL-PRO), 4,4'-bipyridine (THC-BPY), and betaine (THC-BTN) were discovered for the first time using liquid-assisted grinding. Single crystal structures of all THC cocrystals were analyzed and comprehensive characterization was performed through PXRD, thermal analysis, DVS and FT-IR. Dissolution studies were further conducted on two edible cocrystals THC-L-PRO and THC-BTN, and THC-L-PRO exhibits the highest apparent solubility compared with THC-BTN and the raw material. Moreover, THC-Form II was found in THC-L-PRO dissolution experiments, and subsequently, melt crystallization method was used to obtain the pure form of THC-Form II. THC-Form II was characterized for its physicochemical properties and the result of dissolution experiment showed better solubility compared to THC-Form I.