The invention discloses a yield increasing system and method for coal bed gas wells and belongs to the field of natural gas exploitation. The yield increasing system for the coal bed gas wells comprises a screw compressor, a gas inlet pipeline, pumping and discharging pipelines, pumping and discharging valves, an exhaust pipeline, an outward delivery pipeline, gas collecting pipelines and gas collecting valves, wherein coal bed gas wellheads, the gas collecting pipelines and the outward delivery pipeline are connected sequentially to constitute a first discharging and mining channel; and the coal bed gas wellheads, the pumping and discharging pipelines, the gas inlet pipeline, the screw compressor, the exhaust pipeline and the outward delivery pipeline are connected sequentially to constitute a second discharging and mining channel. The pumping and discharging valves are arranged on the pumping and discharging pipelines, and the gas collecting valves are arranged on the gas collectingpipelines. The yield increasing system for the coal bed gas wells is capable of increasing the yield of coal bed gas, and is convenient to use and suitable for being applied and popularized on a largescale.