Density, viscosity, flash point and refractive index for binary mixtures of cis-decalin or trans-decalin with nonane, decane, and undecane have been determined at pressure p = 0.1 MPa and different temperatures ranging from (293.15 to 323.15) K. The calculated excess molar volumes give negative values over the whole composition range for these binary systems. With the increase of mole fraction of decalin, the values of viscosity and refractive index increase continuously. The viscosity deviation and refractive index deviation are calculated, showing negative from the corresponding linear additive values. A small additional amount of the component with lower flash point leads to marked changes of flash point values of these binary mixtures.