The invention discloses a rock-soil detection device for geological exploration. A cutting knife is hinged to the bottom end of a rock sampling barrel, a pressing spring is welded to one end of a pulling rope, a transmission motor is installed at the top end of a soil sampling barrel, a sealing limiting plate is clamped to the inner side of a discharging opening, and a soil collecting box is clamped to the side end of an installation connecting frame. Rock is sampled through the rock sampling barrel, the angle of the cutting knife is changed through the pulling rope and the pressing spring, so that the cut rock core can be conveniently and rapidly lifted, personnel can conveniently and visually observe, the soil is sampled through the soil sampling barrel and the auger, and the soil is discharged through the discharging port, the soil at different depths can be rapidly screened when needing to be collected, the situation that the soil is mixed together to influence the detection result is avoided, rock collection and soil collection are separated, mutual interference is avoided, and the situation that the detection result deviates due to mutual influence is avoided.