A movable soil crushing and screening combined device comprises a frame body. A soil crushing device, a conveying device and a soil screening device are installed on the frame body. The soil crushing device is connected with the soil screening device through the conveying device. In the soil crushing device, a first-stage soil crushing mechanism, a second-stage soil crushing mechanism and a third-stage soil crushing mechanism are sequentially installed in a soil crushing cavity from top to bottom. The first-stage soil crushing mechanism is composed of two first-stage gears arranged on the upper portion in the soil crushing cavity in an engaged mode, the second-stage soil crushing mechanism is composed of two second-stage steel pillars in a transversely connected mode, and the third-stage soil crushing mechanism is formed by two third-stage gears in an engaged mode. According to the movable soil crushing and screening combined device, the problem in the prior art that a soil screening machine can not achieve soil crushing and soil screening at the same time is solved, integrated operation of soil block crushing and screening is realized, the soil crushing and screening operation in an experiment is facilitated, time and labor are saved, and operation efficiency is improved.