Abstract: The measurement of equilibrium flow curves of thixotropic waxy crude oil is the most important basic work in the process design of storage and transportation system of crude oil. During using the measurement standard of the SY/T 0520-93 of the P. R. C, there are a few disadvantages, i, e., more calculations, long time waiting for the manual operation and no a criterion for the software automatic operation. Through analyzing the standard and laboratory testing, the authors have found a very useful criterion for the manual and automatic software measurement operation of rheometer or viscometer, it is dlnt/dt < 8.35z10-5