thermodynamics. The entropy is assumed to be proportional to the area of the local Rindler horizon of an infinitely accelerated Rindler observer. The temperature of the system in consideration is taken as the Unruh temperature sensed by this observer. This study starts from equilibrium thermodynamics, but the resulted Einstein equa-tion can be used in a general case. One is justified to guess that there is some technical problem in the reasoning. The technical de-tails of this problem are pointed out in [3]. The order of the local Killing vector is displayed to be problematic. Verlinde suggests an entropic force method, which can also derive Einstein field equa-tion from thermodynamics [4]. Different from Jacobson’s approach, Verlinde supposes a stationary spacetime from the very beginning. It seems reasonable to assume the spacetime to be in equilib-rium, and thus the application of equilibrium thermodynamics is guarantied. The entropic force approach has been extended to sev-eral other cases [5]. However, some problems have been found in the entropic force method. For instance, the experiments by using ground based ultra-cold neutrons seem contradicting to the con-cept of entropic force [6].