The invention discloses an undistributed soil sampling device and a sampling method, belonging to the technical field of geotechnical investigation and providing an undistributed soil sampling device and an undistributed soil sampling method which have little disturbance to undistributed soil, do not easily cause loosening of sampled soil, and are convenient for sampling, packaging and subsequent transportation and transfer of the undistributed soil. The undistributed soil sampling device comprises a sampling tube body having two open ends, and a force applicator, wherein the force applicator comprises a lantern ring and a force transfer handle; a clamping ring bulge is arranged on the outer peripheral wall of the top of the sampling tube body and is lower than the top end surface of the sampling tube body; the lantern ring is detachably sheathed on the sampling tube body above the clamping ring bulge. The device disclosed by the invention is simple in structure; the sampling tube body can be completely pressed under the surface of the soil, such that the undistributed soil can be completely full of the whole sampling tube body to effectively avoid the situation of soil loosening; the device is also convenient for manual application of force to reduce the disturbance to the undistributed soil in a force application process and improve the sampling success ratio of the undistributed soil.