The invention discloses a portable shallow soft soil original state sampling device and a sampling method. A solution is provided for solving the problems that soft soil with a high water content is likely to fall along the inner wall of a sampler, an original state soil column is easily disturbed in repairing, separating and post-treating processes, and the inner cavity of the sampler is difficult to clean and the like. The sampling device comprises the sampler, a positioner and a separator. Smooth sampling is realized through a sampling rod, a steering base, a force transfer base and a sampling barrel; a negative pressure is generated in the inner cavity of the force transfer base by virtue of a piston and a baffle plate, so that a soil sample is prevented from falling. By opening out a liner pipe and the separator, the soil column is repaired, separated and packaged. The method comprises the following steps: removing miscellaneous soil in the surface layer, assembling the sampling device, and pressing the sampler into a specific depth; then lifting up the sampling rod to close the inner cavity of the force transfer seat; and screwing the sampler out, detaching the sampling barrel, pushing the liner pipe out by using the separator and performing packaging with a cover. The device disclosed by the invention is simple in structure, convenient to operate, small in sampling disturbance and high in efficiency.