The invention discloses a preparation device of nutrient soil for rice planting. The device comprises a screening box, wherein a hopper is communicated with the top of the screening box, a first motoris installed on the top of the screening box, an output shaft of the first motor is inserted into the interior of the screening box and connected with a rotating shaft, a crushing rod is fixed at theside edge of the rotating shaft, a first spiral shaft is connected with the bottom end of the rotating shaft, a funnel and a sieve plate are mounted inside the screening box, the first spiral shaft is located in the funnel, the sieve plate is located below the funnel and arranged obliquely, an exciter is mounted at the bottom of the sieve plate, a sliding groove is formed in the bottom in the screening box, a receiving box is arranged in the screening box, rollers are mounted at the bottom of the receiving box and mounted in the sliding groove in a rolling manner, and a feeding passage is mounted at the side edge of screening box. The device is not easy to block, raw materials are crushed efficiently and circularly, automation of processing is achieved, and the crushing rate is very high.