The invention provides a sampling device for geological fluid detection, relates to the technical field of fluid detection. The sampling device comprises a support frame, the support frame is of an L-shaped structure, and a second support plate is arranged at an upper portion of the support frame; the protection cover is mounted at the corner of a bottom portion of the support frame. The water fixing member is clamped above the bottom portion of the support frame; the locking inclined block is mounted at the bottom portion of the; and the detector is provided with a water inlet pipe. Fluid at different depths is detected through cooperation of the mounting sleeve and the lifting frame, a fluid drainage tube is wound around the winding wheel, the mounting sleeve is driven by the lifting frame to adjust the position through the arrangement of the gear and the rack, the fluid is sampled through the sampling test tube.