Objective To investigate the influences of polyethylene glycol on the solubility and in vitro dissolution of m-nisoldipine,which could provide guidance for chosing formulations of m-nisoldipine. Methods Solid dispersions of m-nisoldipine were prepared by solvent-melting method with polyethylene glycol6000 matrix. DSC and XRD spectroscopy were applied to identify the solid dispersions. The solubility and in vitro dissolution were detected by UV spectroscopy. Results The DSC and XRD map were different from the crude drug and their physical mixtures. The dissolution rates(13,15,17) were faster(35. 31%,38. 71%,41. 48%) than that of the crude drug(26. 80%),and the dissolution rates of the solid dispersions in the same ratio were higher than the physical mixtures. Conclusion DSC analysis indicated that eutectic compounds were produced by the m-nisoldipine and polyethylene glycol,in which polyethylene glycol6000 acts as a carrier. The solubility and in vitro dissolution of m-nisoldipine can be increased.