The invention relates to a novel 
crystal form of 
argatroban and a preparation method thereof. The novel 
crystal form has characteristic peaks at 4.3+ / -0.1, 7.4+ / -0.1, 8.5+ / -0.1, 8.8+ / -0.1, 10.4+ / -0.1, 10.7+ / -0.1, 17.2+ / -0.1, 17.9+ / -0.1, 20.3+ / -0.1, 22.5+ / -0.1, 27.8+ / -0.1 and the like by 
diffraction angle 2theta. The preparation method comprises the following steps: dissolving an 
argatroban coarse product in a mixed 
solvent of 
ethanol and water to prepare 
argatroban liquor; heating to 40-75 DEG C, and stirring, dissolving and clarifying; then, cooling and recrystallizing, filtering, 
vacuum drying to obtain the novel 
crystal form of argatroban. The product is uniformly paved in an opened culture dish, wherein the thickness of a sample is less than 5mm and the sample is hermetically placed in a drier at 50-80 DEG C, X-
Ray Diffraction detections are carried out on samples respectively in 30 days and 60 days, the results are compared with the result at the 0th day, and the result shows that the novel crystal form of argatroban does not changed and is good in stability.