According to a geological and geotechnical investigation strength test sampling device provided by the invention, a soil sample can be completely taken out under the condition that the soil sample is not crushed, and meanwhile, the structure of the taken-out soil is not changed, and additional internal stress does not exist, and therefore, the taken sample can accurately reflect the actual condition in the current soil layer; and according to the technical scheme, the sampling device comprises a drilling machine and is characterized by further comprising a sampler installed on the drilling machine, the sampler comprises a sampling barrel, the sampling barrel is divided into an upper cavity and a lower cavity through a partition plate, a cutting layer is coaxially and fixedly connected to the inner side wall of the lower cavity, cutting edges are arranged at the lower ends of the cutting layer and the spiral channel, a guide rod which is coaxially arranged is fixedly connected into the upper cavity, a pressing rod is vertically connected into the guide rod in a sliding mode, the lower end of the pressing rod downwards extends into the lower cavity, a vertically-arranged threaded hole is formed in the upper end of the pressing rod, and a pressing disc is arranged at the lower end of the pressing rod.