The inclusion complex of sinomenine(SN) to hydroxypropyl-β-cyclodextrin (HP-β-CD) was prepared successfully through mixed solution method, then the crystalline morphology and micromorphology of the inclusion complex was characterized and analyzed by stereomicroscope after purification and recrystallization. Other material behaviors of the inclusion complex of sinomenine to HP-β-CD were characterized through X-ray diffraction(XRD), infrared spectrography(IR), differential scanning caborimetry(DSC) and hydrogen nuclear magnetic resonance(HNMR),and then the formation constant of inclusion complex was determined by phase solubility analysis. The results present that the inclusion complex of SN to HP-β-CD show obvious characteristics compare to SN, the inclusion complex of SN to HP-β-CD was new material form and HP-β-CD can sharply increase the solubility of SN. The molecular ratio of SN to HP-β-CD was 1:1 and the inclusion constant was calculated as 150.0 L/mol.