A deformation test device inside a soil-
mass belongs to the technology field of
geotechnical engineering test. The invention includes a deformation coordinating tablet, a displacement transmission rod, a soft casing and a displacement meter, wherein the deformation coordinating tablet is pre-buried in the position to be determined in soil, the centre of the deformation coordinating tablet is fixedly connected with the displacement transmission rod, the other end of the displacement transmission rod is connected with the displacement meter, the displacement transmission rod is located in the soft casing, and the displacement transmission rod is isolated from the outside soil-
mass by the soft casing. The invention has simple structure, convenient
processing and simple operation, which is applied for geotechnical
model test and can conveniently test the displacement inside the soil-
mass, and the results are accurate and reliable.