Two kinds of sweet potato puree were prepared with Benihayato cultivar of yellow sweet potato with or without $alpha$-amylase enzyme treatment. Chemical and rheological properties of enzyme-treated puree were different from those of control puree. Reducing sugar content and iodine value increased by $alpha$-amylase enzyme treatment, while alcohol insoluble solids and viscosity decreased by enzyme treatment. However, the changes of carotenoid content were not significantly different. Hunter-b-values(yellowness) were 27.19 and 23.54 for no enzyme-treated puree(NTP) and enzyme-treated puree(ETP), respectively. Hunter-a values(redness) were 2.24 and 6.05 for NTP abd ETP, respectively. Content of total carotenoid of canned puree heated at 13$0^{circ}C$ for 30 min decreased by 59 percents.