The invention relates to an externally-moving and internally-stationary cutting ring soil sampling device and soil sampling method. The soil sampling device comprises a first connector, a connecting section and an external moving pipe which are sequentially fixedly connected, wherein the external moving pipe is provided with a cutting edge, a buffering mechanism is arranged in the external movingpipe, and connected with the external moving pipe and an internally static pressure cutting ring sampling pipe, and the internally static pressure cutting ring sampling pipe extends out of the external moving pipe; a clearance is left between the internally static pressure cutting ring sampling pipe and the external moving pipe; a cutting ring is arranged in the internally static pressure cuttingring sampling pipe, the middle section of the internally static pressure cutting ring sampling pipe is connected with a second connector and a pipe edge through a connecting mechanism, and the secondconnector is connected with the buffering mechanism. The soil sampling method comprises the following steps: applying pressure to the internally static pressure pipe, leading the pipe edge to penetrate into a soil layer at the bottom of a drill hole at static pressure, driving the external moving pipe to rotationally cut soil through a drill rod, and leading the internally static pressure cuttingring sampling pipe to be penetrated into the soil layer for sampling; stopping drilling, taking down the soil sampling device, separating the internally static pressure cutting ring sampling pipe fromthe buffering mechanism, taking down the second connector and the pipe edge, separating the assembly, taking out the cutting ring, to obtain a cutting ring sample. The cutting ring sample obtained through soil sampling device meeting the requirement of I-level undisturbed samples, and the quality and the efficiency of geotechnical engineering investigation can be improved.