The invention discloses a full-transparency fabricated multifunctional geotechnical engineering model case capable of achieving three-dimensional dimension adjustment. The model case comprises a steelbottom plate, a steel framework and soil blocking face plates. The steel bottom plate is located at the bottom of the model case. The steel framework is located on the periphery of the model case andis composed of steel angles and steel channels. The soil blocking face plates are located in the model case and are composed of corner organic glass modules and conventional organic glass modules. According to the model case, transparent organic glass modules are adopted as the soil blocking face plates, full transparency of the model case can be achieved, and it is beneficial to visualization ofthe whole process of deformation of a test model structure and soil changes on the periphery of the test model structure in the model case. Meanwhile, the transverse and perpendicular dimensions of the model case can be adjusted by adjusting overlapping of the outer framework and the number of soil blocking face plate module units. The model case can be used for developing relative tests such asthe influences of tunnel excavation on existing buildings and influences of ground stacking on subway structures. The model case has the advantages of being fully transparent, capable of adjusting thedimensions in three dimensions, convenient and fast to disassemble and assemble and rich in function.