Abstract: For low control precision and work efficiency of existing rodless drainage equipments of coalbed methane and large labor intensity in drainage field, a hydraulic pressure driven rodless pump was designed as well as a hydraulic pressure driven rodless drainage control system based on PLC. The system uses underground pressure transmitter to measure bottom-hole flow pressure and PLC to control inverter to adjust motor speed through comparing measured flow pressure with the set one, so as to adjust bottom-hole flow pressure. The hydraulic pressure driven rodless pump does reciprocating motion, which is driven by power fluid in power fluid pipe of three-channel oil pipe, so as to realize automatic up-down switching between valves without labor operation. The experimental result shows that the system can adjust bottom-hole flow pressure to approach the set one quickly and correctly with small overshoot.