The invention discloses a portable soil respiration measuring device and belongs to the field of soil detection. The device comprises a motor, a fixing barrel and a rotation mechanism, wherein the rotation mechanism is positioned in the fixing barrel and comprises a hollow rod and a turntable, the outer wall of the turntable is in threaded connection with the inner wall of the fixing barrel, one end of the hollow rod is fixedly connected with the turntable, a soil guide spiral blade is arranged outside the hollow rod, a CO2 detector is arranged in the hollow rod, and the CO2 detector faces anopening of the fixing barrel; the motor is positioned at the outer side of the fixing barrel, an air cylinder is fixed between the fixing barrel and the motor, a through hole is formed in the bottom of the fixing barrel, an output shaft of the motor is fixedly connected with a rotary shaft, the rotary shaft penetrates through the through hole and the turntable and is in threaded connection with the turntable, a meshing section is arranged on the rotary shaft, and the meshing section is meshed with the through hole. The device can improve the accuracy of CO2 detection and directly carry out soil backfilling after the detection is finished.