A constant-pressure variable-flow insufflator, comprising a housing, wherein an insufflator gas inlet, an insufflator gas outlet, a smoke removal gas inlet, and a smoke removal gas outlet are respectively provided on an outer side of the housing; the insufflator gas inlet is connected to an external gas source through a pressure relief valve A; the insufflator gas outlet is connectable to an abdominal cavity of a patient through a filter A; the smoke removal gas inlet is connectable to the abdominal cavity of the patient through a filter B; the smoke removal gas outlet is communicated 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 housing; the control module is in signal connection with each of the pneumatic module, the temperature detection module, the safety module, the temperature control module, and the smoke removal module for driving a system and performing digital signal processing on collected data; the pneumatic module is configured for controlling pressure, temperature, and flow of gas delivered by the external gas source; the temperature detection module is configured for detecting the temperature of the gas delivered by the external gas source; the safety module is configured for detecting temperature of the control module and the pneumatic module; and the temperature control module is configured for reducing noise while cooling an interior of a chassis; and the smoke removal module is configured for exhausting smoke generated in the abdominal cavity of the patient, wherein the pneumatic module comprises a filter C, a pressure sensor A, a heating pressure relief valve, a safety valve, a pressure sensor B, a proportional valve module, a flow sensor, and a switching valve module; one end of the filter C is connected to the insufflator gas inlet through a pipeline, and another end of the filter C is connected to the heating pressure relief valve through the pipeline; another end of the heating pressure relief valve is connected to one end of the safety valve through the pipeline; another end of the safety valve is connected to the proportional valve module through the pipeline; one end of the proportional valve module is connected to one end of the flow sensor through the pipeline; another end of the flow sensor is connected to one end of the switching valve module through the pipeline; another end of the switching valve module is connected to the insufflator gas outlet; the flow sensor is in signal connection with the control module; the pressure sensor A is arranged on the pipeline between the filter C and the heating pressure relief valve; the pressure sensor A is in signal connection with the control module; the pressure sensor B is arranged on the pipeline between the safety valve and the proportional valve module; and the pressure sensor B is in signal connection with the control module; and wherein the safety module comprises a temperature sensor C and a temperature sensor D; the temperature sensor C is arranged on an outer side of the heating pressure relief valve; the temperature sensor C is in signal connection with the control module for detecting a temperature of the heating pressure relief valve; and the temperature sensor D is mounted on the control module, and is in direct signal connection with the control module for detecting a temperature of the control module.