The invention discloses a cohesionless soil sampling apparatus. The apparatus comprises a cylindrical sampling cylinder, the sampling cylinder comprises a sampling top and a sampling bottom which are in threaded connection, the sampling bottom is provided with a fixed separation blade and a movable separation blade, the fixed separation blade is fixedly arranged on the inner wall of the sampling bottom, the movable separation blade is connected with the fixed separation blade through a center rotating shaft, the movable separation blade is positioned below the fixed separation blade, the center rotating shaft and the sampling cylinder are coaxially arranged, the top surface of the fixed separation blade is formed by two sector-shaped plates symmetrical to the center rotating shaft, the radian of each of the sector-shaped plates is 90DEG, the structure of the movable separation plate is same to the top surface of the fixed separation plate, and the top surface of the movable separation blade and the fixed separation blade are respectively vertical to the center rotating shaft. The bottom of the sampling cylinder can be conveniently closed without loss of a sampling amount, so the soil horizon sampling analysis working accuracy is improved.