The L-type horizontal well is the main type of coalbed methane development. At present， the construction equipment of the L-type horizontal well of coalbed methane in China are all standard oil rigs， but the equipment configuration and transportation cost of the oil rigs are higher. The water source drilling rig purchase cost is lower， farther many geological prospecting units are originally equipped with the water source drilling rig. Therefore， on the basis of studying and summarizing the equipment principle， main parameters and difference characteristics of conventional water source drilling rigs and oil drilling rigs， this paper has carried out 4 improved designs for TSJ-3000 water source drilling rig， to achieve standard oil rig performance. At the same time， according to the geological condition， working environment and construction technology of coalbed methane horizontal well， 4 lifting designs for improving TSJ-3000 water source drilling rig are carried out， includes the mud logging device while drilling， hydraulic tongs， submersible blowdown equipment and pneumatic winch， in order to meet the construction requirements of L-type coalbed methane horizontal well. The application of the improved TSJ-3000 water source drilling rig has effectively improved the working efficiency and economic benefit.