Abstract: The cassava starch was used to prepare cassava hydroxypropyl and octenyl succinic anhydride compound modified starch.The physical properties of cassava hydroxypropyl and octenyl succinic anhydride compound modified starch were investigated by Fourier transform infrared spectrometer (FT-IR) , Scanning electron microscop, X-ray diffraction (XRD) , Brabender viscometer and so on with the comparison of the native cassava starch and octenyl succinic anhydride (OSA) -modified cassava starch.The results indicated that the FT-IR spectrum of compound modified cassava starch showed new absorption peaks at 1550～1610cm-1.and weaken absorption peak at the 940, 880, 730 and 570cm-1, compared with the native cassava starch and OSAmodified cassava starch.The starch granule exhibited rougher surface, more irregular shape significantly but the crystalline was not changed.The product showed good emulsifiability and transparency.That gelatinization temperature and the peak temperature all decreased, and paste viscosity was higher as well.The setback capacity was weaker, and hot paste stability increased, compared with single octenyl succinic anhydride modified starch.