An approach based on the graph theory is used to study the relationship between molar refractions of silane and its molecular structure for the first time in this paper. A quantitative relation is developed which can be used to predict the molar refraction MR of liquid silane at 293K MR=a~0+a~1N+a~2exp(-λD^2^/^3)+a~3S+a~4P where λ and a~i(i=0～4) are constants, and N, D, S and P are respectively the first-order, second-order, third-order and fourth-order structural information indexes defined in this paper. The results calculated show that the predicted values agree with the experimental values satisfactorily, and the average relative and absolute deviations from the experimental values are respectively 0.160 ％ and 0.094(cm^3 / mol) for 25 kinds of silanes.

Key words: SILANE, STRUCTURE AND PROPERTY CORRELATION