The invention discloses a three-in-one vertical desander and a desanding process. The desander comprises a quick opening closure and a vertical barrel, wherein a medium inlet is formed in the upper part of the vertical barrel, a medium outlet is formed in the middle, a backflush port is formed in the lower part, and a sand discharge port is formed in the bottom; a screen pipe is arranged in the vertical barrel, the upper part of the screen pipe is connected with the upper part of the vertical barrel, and the lower part of the screen pipe is connected with the medium outlet; the medium inlet adopts tangent gas inflow, a cyclone guide device is arranged at the medium inlet, a sand storing space is formed below the medium outlet, and a conical funnel is arranged below the sand storing space;an inlet differential pressure gauge is arranged at the medium inlet, and an outlet differential pressure gauge is arranged at the medium outlet. Compared with the prior art, the three-in-one verticaldesander has the positive effects as follows: desanding precision is improved, influence on normal operation of downstream equipment is reduced, time for desanding operation is determined by monitoring desanding time through differential pressure, desanding operation is convenient, and operation difficulty is reduced.