An injective map from type E₇ root system to vector space (Z/2×Z/2)³ over finite field Z/2 was developed.By means to the injective map and the stratification of the root system,the relations of partial order and orthogonality between roots were investigated.The identification method of orthogonality between roots on the same stratum and different strata were provided.The two relations on the seventh stratum were made to be visualized in a cube.Similarly,the two relations on other strata can also be reflected in the cube.