Abstract: Two-dimensional(2D) transition metal dichalcogenide(TMD) crystals have attracted increasing attention due to their diverse structure and unique properties for broad applications.Therefore,the synthesis of high-quality 2D TMD crystals plays a significant role in improving fundamental research and applications,and the solid-state reaction in a vacuum system has been employed as a powerful tool for the growth of high-quality 2D TMD crystals.In this review,we summarized the methods for growing 2D TMD crystals with high quality in a vacuum system and discussed the factors that affect the size,quality,morphology,and polytype of 2D TMD crystals.We also briefly discussed the physical properties and diverse applications of 2D TMD crystals.Finally,perspectives of solid-state reaction in vacuum system on 2D TMD crystals growth are provided.