During drilling shale formation with a large number of micro-nano pores, effectively preventing drilling fluid or filtrate from entering the formation through these micro-nano pores and preventing shale hydration and dispersion is a key technical challenge to prevent wellbore instability, as well as reach safe and rapid drilling.At present, a lot of researches have been done for the evaluation method of nano-particle plugging. But there is no unified standard at present. The extent of reflection on the real plugging effect of nanoparticles in the process of use is also needed to be understood. In this paper we analyze several main sealing evaluation methods, evaluate their effectiveness, and give some suggestions in the conclusion. At present, it is better to reflect the blocking effect by the experiment of high temperature and high pressure permeability loss and experiment of pressure transfer,and it is suggested to further improve the evaluation method of plugging effect of nano plugging agent,which is of great significance for the selection of nano-particle plugging agent for drilling fluid and the evaluation of wellbore stability.