Flour drying can be done by using pneumatic conveying dryer (PCD) or flash dryer, but generally required a vertical pipe that is high enough. High vertical pipe can be replaced with a recirculation process to produce a required final moisture content of the material. This study had designed pneumatic conveying recirculated dryer (PCRD), and seek mathematical model of the relationship between the variables of drying process with final moisture content of the material. The purpose of this study is to develop a mathematical model of the relationship between the final moisture content of the material with variables drying process and recirculation continuously in the pneumatic conveying recirculated dryer (PCRD) using dimensional analysis. Buckingham Phi Theorem methods of dimensional analysis is used to find the relationship variables that affect the final moisture content of the material on the PCRD machine. The mathematical model generated in this study are The coefficient of determination (R2) of the mathematical model is 0.95, or 95 %, this indicates that the model is valid is used to predict the moisture content of the materials in designing PCRD machines. While the sensitivity of the test results showed that the dimensionless product of the most influential are , , and . The model is applicable for drying wet sago starch or other starch material are identical to the physical properties of wet sago starch.