The invention discloses a method and a device for volume measuring of crack soil. The method includes steps: (1), taking a circular wire mesh, symmetrically binding four copper wires on the edge of the wire mesh, taking a voluminal beaker, pouring into liquid paraffin, and placing the beaker containing the liquid paraffin on a balance tray; (2), weighing testing soil sample mass by a balance; (3) adjusting a horizontal extension valve and a vertical extension valve to enable the wire mesh to be totally immersed in the liquid paraffin, reading the balance, and recording integral mass; and (4) adjusting the vertical extension valve to enable an auxiliary device to be lifted, placing a soil sample on the wire mesh, reading the balance, recording the integral mass of the beaker, the liquid paraffin, the copper wires and the soil sample. The beaker containing the liquid paraffin is placed on the balance tray, one end of each copper wire is bound on the edge of the wire mesh, the other end of each copper wire is bound on a horizontal supporting rod which is connected with a vertical supporting rod, and a support is connected below the vertical supporting rod. The method is easy, operations are simple and convenient, and volume measuring of crack soil sample is higher in accuracy.