The invention discloses a mobile plastic crushing and conveying device. A turnover platform is arranged below a cut-off mechanism; a feed inlet and a discharge outlet are formed in a shell; a cutter can stretch out and draw back towards a baffle in a reciprocating mode; the side walls between two roll shafts are mutually engaged; crushing cutters are arranged at the same end of the multiple roll shafts, and the roll shafts are connected to a drive mechanism; a screening mechanism is further arranged at the position, between the discharge outlet and the crushing cutters, in the shell; the screening mechanism comprises a screen box, a vibration spring and a vibrator fixed to the side wall of the screen box; a metal filter plate is arranged between the turnover platform and the crushing cutters; a supporting framework is fixedly connected to the outer bottom of the shell, and a plurality of self-locking type universal wheels are arranged at the bottom of the supporting framework; the twoends of a plurality of roll wheels are rotationally arranged in corresponding rotating grooves in two strip-shaped plates; and a conveying belt is arranged on the multiple roll wheels in a sleeving mode. The mobile plastic crushing and conveying device can crush waste plastic efficiently and quickly and is convenient to move.