The invention discloses an agricultural planting crushing device for straw treatment. The crushing device comprises a shell, a feeding hopper, a driving device, a base and rollers. A horizontal extruding block is fixed on the output end of the driving device. Extruding plates fixed on the inner wall of the shell are arranged below the extruding block. A plurality of discharging holes are uniformlyformed in each extruding plate. A plurality of extruding columns corresponding to the discharging holes are fixed on the lower side of the extruding block. A plurality of discs arranged at an equally-spaced manner are fixed on each extruding column coaxially. Dust removal cavities are formed in the outer sides of a discharging barrel and crushing cavities. According to the invention, falling straw is extruded by the discs on the extruding columns, and then are taken into the discharging holes, so as to enable the extruding block to drive the straw to fall smoothly, without the need of manualpressure application; and power of the driving device is utilized reasonably, energy is sufficiently utilized, and the falling straw is extruded by the extruding block, so that rotary cutting of the straw is facilitated, the refining treatment by crushing rollers is facilitated, load of the straw is reduced, and the crushing stability of the straw is improved.