Abstract: Taking sweet potato, potato, taro, pumpkin and sugarcane as raw material, five kinds of natural flavors with roasted sweet aroma were prepared through high temperature roasting, water and ethanol extraction. The sugars and volatile components of the raw materials were determined by HPLC and GC/MS respectively, and the correlation relationship of total sugar and reducing sugar contents with contents of volatile components and roasted sweet aroma components in roasted materials were analyzed. An approach to screen raw material used for preparing natural flavors with roasted sweet aroma was developed. Sensory evaluation was conducted to verify the approach. The results showed that:1) Most of the volatile components in roasted material were Maillard reaction and/or caramelization products, and Maillard reaction and/or caramelization could play a key role in formation of volatile components. 2) The reducing sugar contents in roasted materials had a close relation with contents of their roasted sweet aroma constituents, thus the key indicators for screening raw material were glucose, fructose and maltose contents. 3) Roasted sweet potato and pumpkin had higher reducing sugar contents and production of roasted sweet aroma components, they were more suitable for preparing natural flavors with roasted sweet aroma. The application of natural flavors could be preliminarily predicted according to the contents of reducing sugars and roasted sweet components in the roasted material.