Porous starch granules were formed by the partial hydrolysis of starch using amylase. Fungal amylase and corn starch were chosen as the original amylase and substance from different sources, respectively. Ultrasonic technique as an assistant of enzymatic hydrolysis was used to pretreat raw starch. Scanning electron microscopy was used to examine the structure of native and treated starch, revealing the size of the pores in each occasion. The extent of enzymatic hydrolysis (y%) was markedly enhanced by statistical optimisation of enzymatic conditions. A significant influence of amount, temperature and pH of enzyme has been noted with Plackett-Burman design. It was then revealed with response surface methodology (RSM) that 503.26 U (g substance) )1 amount of enzyme, temperature of 55°C and pH of 5.1 were optimum. This optimisation strategy led to the enhancement of y% from 53.4% to 61.38%.