The　layered　semiconductor　compound,　as　transition　metal　dichalcogenide　family　MX2　(M=Mo,　W,　X=S,　Se)　had　stirred　common　interesting　in　solar　energy　conversion　for　its　special　photoelectronic　properties.　The　synthesizing　of　its　single　crystal　free　of　surface　defects　is　a　pressing　matter　of　the　moment.　In　this　paper,　the　key　points　in　preparing　such　single　crystal　are　concluded,　that　is　high　vacuum,　long　time,　and　small　∆T,　sometimes　the　transport　agents　have　to　be　used　to　help　the　matter　diffusion.　And　the　proper　quantities　of　these　parameters　are　detailed　in　this　paper　too.　©　Journal　of　Physics:　Conference　Series　2021.