An EP (extreme pressure) lubricity tester is an indoor test analysis instrument, and cannot achieve the on-line real-time monitoring of well drilling. The invention provides an extreme pressure lubricity tester for the on-line real-time monitoring of well drilling. In order to achieve the above purpose, a test EP lubricity tester used in a laboratory is reconstructed. Firstly, a pressing mode through a torque wrench is changed into a mode of automatic pressing controlled through a computer, the rotating speed of a sliding ring is set as 60 turns per minute, the acting force of a sliding block on the sliding ring is 444.8N, and the coefficient of friction resistance of distilled water is 0.34; secondly, a collected motor current data signal is transmitted to a collection module of a well-drilling real-time monitoring system through a PLC or other programmable controller and a cable or a wireless data transmission module, and becomes a part of the well-drilling real-time monitoring system; thirdly, the well-drilling real-time monitoring system measures the working time and program of the extreme pressure lubricity tester, and he working time of the program are controlled by a computer through a programmable controller. The extreme pressure lubricity tester is shown in an attached figure.