The utility model provides a quick connecting device for a wellhead test of an oil-water well. The quick connecting device can be applied to detection of oil pressure, oil temperatures, water pressure and water temperatures of various oil-water well wellheads in oil fields, and is quickly connected with a temperature transmitter and a pressure transmitter. The quick connecting device comprises a test instrument connection sleeve, a temperature measuring tube and a pressure measuring tube. The temperature measuring tube penetrates through an inner cavity of the test instrument connection sleeve, and the pressure measuring tube is communicated with the inner cavity of the test instrument connection sleeve. The temperature measuring tube and the pressure measuring tube are welded to the test instrument connection sleeve, and the test instrument connection sleeve is provided with an external thread to be connected with an oil tube screwed plug mounting hole. The quick connecting device can be used for measuring temperatures and pressure, on-site electrogas welding is of no need, mounting and manufacturing cost is saved, mounting is easy and convenient, and potential safety hazards are avoided. Material cost is saved, well stopping mounting time is shortened, the phenomenon of crude oil output reduction caused by long-time well stopping is reduced, meanwhile, major safety accidents probably caused by welding flame operation can be avoided, and an obvious using effect is achieved.