The objective of this work was to investigate the existence of polymorphs of SK-3530 and the transformation of crystal forms. Two crystal forms of SK-3530 have been isolated by recrystallization and characterized by differential scanning calorimetry, powder X-ray diffractometry and thermogravimetric analysis. The differential scanning calorimetry and powder X-ray diffractometry patterns of two crystal forms were different respectively. After storage of 1 month at 0% RH (silica gel, $20^{circ}C$), 52% RH (saturated solution of $Na_2Cr_2O_7{cdot}2H_2O/20^{circ}C$) and 95% RH (saturated solution of $Na_2HPO_4/20^{circ}C$), Form 2 was not transformed to Form 1 and two forms were shown to have a good physical stability at room temperature for 1 month. In the dissolution studies in pH 6.8 buffer at $37{pm}0.5^{circ}C$, the dissolution rate of Form 2 was significantly higher than that of Form 1 under 30 min.