The utility model relates to a log tool for an oilfield, in particular to aUHT (ultra-high-temperature) four-parameter log tool. A single-chip microcomputer main board of the log tool adopts a 24-bit AD converter, the upper end of an inner tool tank is connected with a salvaging cap and a high-temperature turbine flowmeter, an impeller of the high-temperature turbine flowmeter is made of a titanium alloy, one end of the inner tool tank is inserted into a vacuum flask, the inner tool tank and the vacuum flask are connected through fastening nuts and sealed by a red copper sheet, magnetic steel on the inner tool tank is placed outside the vacuum flask, the vacuum flask body is designed into double-layer housings, a vacuum state is kept between the double-layer housings, the lower end of the inner tool tank is connected with a battery housing, and the bottom end of the vacuum flask is connected with a rope socket. The UHT four-parameter log tool has the advantages that the working time in a deep-well UHT environment is long, the parameter measurement is stable, simple maintenance is facilitated and ground UHTtesting requirements of Kenya are met, and the defects of short working time in the deep-well UHT environment, unstable parameter measurement and maintenance inconvenience are overcome.