In order to obtain optical properties of farm products, the double-integrating-sphere system was designed. The principle of measurement and configuration of system was described. The mixed solution of Intralipid and Evans Blue was detected to verify the veracity of the system by using a diode laser at 650 nm. Corresponding values of the optical properties for scattering coefficient μs, absorption coefficient μa, anisotropy coefficient g measured on pure milk sample were 27.719±0.836, 0.014±0.001, 0.846±0.002, respectively. The authors compared the values of optical parameters based on the double-integrating-sphere system with other measuring methods and obtained a <5% relative deviation. It is concluded that the method for determining the optical properties in agriculture products(vegetables, leaf, tissue of animals, milk etc.) based on double-integrating-sphere system is feasible.