The utility model relates to an external connection type test barrel for inhabiting lateral deformation. The external connection type test barrel comprises an upper part barrel body and a bottom barrel body, wherein a barrel cover is arranged on a top open opening of the upper part barrel body, a concave table is processed on the lower end inner wall along the circumferential direction, the lower side of the upper part barrel body is provided with a bottom barrel body with the sealed bottom, the upper end of the bottom barrel body is processed into an annular convex table anastomotic with the lower end concave table of the upper part barrel body, the height of the convex table is identical to the depth of the concave table, and the thickness of the convex table is identical to the width of the concave table, so that the inner diameter of a straight barrel formed after the sleeving connection of the upper part barrel body and the bottom part barrel body is uniform, the lateral deformation of the test soil body can be effectively inhabited, the deformation in the vertical direction is maintained, the accuracy and the reliability of the test result are ensured, the sections of the barrel bodies in the middle part can be increased or decreased along with the sample loading height and compacting height adaptation, after the test soil sample taking is completed, the barrel body separation can also be used, a layer of barrel body is dismounted every time when a pair of soil samples are taken out, convenience and labor saving are realized, the sample taking time is obviously shortened, and the carrying difficulty of the test device is reduced.