The invention relates to a loaded expanding test method and a loaded expanding test apparatus. The test method comprises: preparing a sample according to the regulation of a loaded expanding test method, placing the sample into a consolidometer, arranging a water permeable stone plate with a diameter of more than a ring cutter diameter on the upper end surface of the sample, stacking the cover plate of the consolidometer onto the water permeable stone plate, applying a set load P on the sample, and carrying out a loaded expanding test. According to the apparatus, the water permeable stone plate with the diameter of more than the ring cutter diameter is additionally arranged in the existing loaded expanding test apparatus. According to the present invention, the test method is simple, the operation is convenient, the structure is reasonable, and the measured loaded expanding rate of the expanding soil is more consistent with the actual situation by strictly controlling the initial state of the sample; and with the method and the apparatus, the technical problem that the expanding soil moisture expansion deformation capacity can be accurately evaluated in the field is solved, and the method and the apparatus are suitable for engineering application.