The invention discloses a soil moisture detection instrument capable of detecting deep soil moisture, which includes a detector probe, a detector main body, a telescopic rod, a handle, a wire through hole, a rubber protective layer, a spiral blade, and a wire reel; Beneficial effects: the handle of the present invention is connected to the probe of the detector probe through the telescopic rod, and the probe of the detector probe is provided with a spiral blade. When the handle is rotated, the probe moves downward under the action of the spiral blade and drives The telescopic rod moves downward, and the telescopic rod can be extended and shortened, which is convenient for moving and placing while satisfying deep-level soil moisture detection. The lead wire of the detection instrument probe of the present invention is arranged inside the telescopic rod, which has a certain protective effect on the lead wire, and avoids that the lead wire is damaged during the process of inserting into the soil, thereby causing damage to the detection instrument; the present invention can not only penetrate deep into the soil measurement, and the operation process is simple.