The invention discloses a product boxing and stacking machine. The product boxing and stacking machine comprises a fixing base, a first installation frame and a second installation frame which are detachably connected to the fixing base, and a conveying assembly which is arranged on the first installation frame and the second installation frame, the conveying assembly comprises an assembling plate, a driving shaft, a first auxiliary shaft and a second auxiliary shaft as well as a conveying belt, wherein the driving shaft, the first auxiliary shaft and the second auxiliary shaft are rotationally connected to the assembling plate, the conveying belt sleeves the driving shaft, the first auxiliary shaft and the second auxiliary shaft, the driving shaft can be further connected to the assembling plate in an up-down sliding mode, the first auxiliary shaft can be connected to the assembling plate in a left-right sliding mode, the driving shaft is located between the first auxiliary shaft andthe second auxiliary shaft; the first auxiliary shaft, the second auxiliary shaft and the driving shaft forms an inverted triangular structure, a driving motor is further arranged on the assembling plate, and the driving motor is in linkage with the driving shaft. According to the product boxing and stacking machine, the conveying distance can be adjusted so that more applicable range can be increased, and the machine can be adapted to more installation places.