The present invention discloses a water sampling device for water conservancy and reservoirs. The device comprises a bracket, and a guiding sleeve is arranged on top of the bracket, a guiding rod is slidably connected within the guiding sleeve, one end of the guiding rod is provided with a driving mechanism, and the other end of the guiding rod is connected with a rack, and a cross rod is connected to one side of top of the bracket, and a bearing seat is embedded at one end of the cross rod, a first rotating shaft is connected within the bearing seat, upper end of the first rotating shaft is sleeved with a gear, and the gear is meshed with the rack, a fixing plate is connected to lower end of the first rotating shaft, a cylinder is respectively arranged at both ends of bottom of the fixingplate, a piston rod of the cylinder is connected with a lifting plate, a first motor is arranged at top of center of the lifting plate, an output shaft of the first motor passes through the lifting plate and is connected with a second rotating shaft, a bottom plate of the second rotating shaft is connected with a take-up drum, and two ends of bottom of the lifting plate is respectively provided with a first water sampling mechanism and a second water sampling mechanism. The device is convenient and quick to use, makes sampling more dispersed, is more universal, has sampling process that is simple and easy to operate, and improves work efficiency.