Deepwater water temperature measuring instrument

A deepwater water temperature measuring instrument comprises a lead retraction and extension metering device, a temperature measuring device and a box. A handle in a winding device is fixed onto a rotary drum sleeved on a support shaft. A length metering device comprises three support rods, two nylon sleeves, a rubber wheel and a depth counter, wherein the three support rods are fixed in the box and sleeved with the two nylon sleeves and the rubber wheel respectively. A support arm is fixed in the box by the aid of a third spring, the rubber wheel contacts with the first nylon sleeve, the upper end of the support arm contacts with the depth counter, and a second protrusion of the support arm is capable of contacting with a first protrusion of the rubber wheel. The temperature measuring device comprises a sensor, a coupler and a digital instrument, wherein the digital instrument is connected with the coupler, the sensor comprises a temperature measuring probe and a contact switch, the coupler is connected with