OBJECTIVE： To study the effects of particle size of ticagrelor crude drug on in vitro dissolution behavior of Ticagrelor tablets. METHODS： Ticagrelor crude drug and different particle size of ticagrelor powder A， B， C， D， E after smashing for different time （15， 30， 40， 60 s） were used to prepare the tablet by wet granulation method. Accumulative in vitro dissolution rate of prepared tablets within 60 min were determined by UV spectrophotometry at 300 nm （using 0.2％ tween as medium， paddle method）. Using original tablet as reference preparation， the similarity factor （f2） method was used to compare the similarity of dissolution behavior between 5 prepared tablets and original tablet. RESULTS： d（0.9） of powder A， B， C， D， E were 69.181， 40.778， 24.805， 12.611， 3.083 μm， respectively. The corresponding f2 were 27.77， 36.79， 50.06， 67.68， 79.99. CONCLUSIONS： The particle size of ticagrelor crude drug is much smaller， and the dissolution behavior of prepared tablet is closer to that of original tablet. The in vitro dissolution rate of Ticagrelor tablets is improved remarkably by micronization technology. In order to produce Ticagrelor tablets with the same bioavailability as original tablet， particle size of ticagrelor crude drug powder should be controlled with     d（0.9）≤20 μm.