In order to meet the high quality, high efficiency and high speed in hydrological well construction, the SPT-1500 trailer-rig is designed, which is a rotary rig with direct and reverse circulation, mainly consists of the trailer frame, power systems, drill, rotary table, hydraulic system, pneumatic system, derrick and drilling system, etc. The test and application show that SPT-1500 trailer-rig has advantages of simple structure, easy installation, rapid transition and steady performance; it has drilling capability to deal with the hydrological well of 1500m in depth and can meet the requirements of various stratum drilling.