The invention provides a constant-pressure variable-flow pneumoperitoneum machine. The constant-pressure variable-flow pneumoperitoneum machine comprises a shell, and a pneumoperitoneum machine air inlet, a pneumoperitoneum machine air outlet, a smoke removal air inlet and a smoke removal air outlet are correspondingly formed in the outer side of the shell. The pneumoperitoneum machine air inlet is connected with an external air source, the pneumoperitoneum machine air outlet is connected with an abdominal cavity of a patient, the smoke removal air inlet is connected with the abdominal cavityof the patient, and the smoke removal air outlet communicates with a vacuum extractor. A control module, a pneumatic module, a temperature detection module, a safety module, a temperature control module and a smoke removal module are arranged in the shell. The control module is correspondingly in signal connection with the pneumatic module, the temperature detection module, the safety module, thetemperature control module and the smoke removal module. According to the constant-pressure variable-flow pneumoperitoneum machine, a traditional air inlet mode is improved, constant-pressure variable-flow control over gas is achieved, the error range of a pressure adjusting interval is small, the change of gas supply flow is stable and uniform, smoke caused by intraperitoneal electrosurgical product work in the operation process can be eliminated in time through the linkage of the smoke removal module and the pneumatic module, and the new clinical requirement for the pneumoperitoneum machineis met.