The invention discloses a pile-supported embankment transparent soil model testing device and method. The device comprises a model groove, transparent soil, a pile body, a water bag, a water pipe, an industrial camera, and a laser emitter. The box-type water bag is placed on the bottom of the model groove made of organic glass. A pile hole position is reserved in the box-type water bag. A pile hole is reserved in the box-type water bag. A pile can be inserted into the pile hole in the box-type water bag. Under the assistance of transparent soil, the soil arch effect of embankment soil under self-weight load can be simulated by discharging the water in the box-type water bag. The invention also discloses a testing method of the testing device. The testing method comprises steps of installing pile and water bag, constructing a transparent soil embankment, slowly discharging water from the water bag, taking pictures of the laser plane by the industrial camera during the water discharging process, and analyzing the pictures to obtain the three dimensional deformation characteristics. The provided device and method have the advantages that high precision realtime measurement on the internal deformation of soil can be achieved, the macroscopic shape change of spacial soil arch can be observed, multiple work conditions can be simulated, the size of the testing device is small, the test operation is convenient, and the efficiency is improved.