Various crustal movements, large-scale volcanic eruptions,seismic activities of different depths and scales,the formation of large-scale mountains and plateaus,and the continental drift movement inEarth’s history are believed to be closely related to plate tectonic activities.But what is the driving force for these events? How to discover and prove their existence and how to understand and explain them in theory is a great challenge for earth scientists.These questions are frontier and hot topics of earth science today and for a long time to come.In recent years,geologists are trying to find the evidence of the dynamics of plate tectonics from Earth’s deeper interior through various methods.First of all,great progress has been made in the study of seismic tomography. Many regional and global high- resolution 3- D seismic mantle wave velocity structures have been obtained, which enables us to understand the deep structure of Earth,and to explore the material composition of mantle, the role of fluids and the dynamic process.It has been shown that plate subduction may reach mantle transition zone,or even the bottom of the lower mantle, and accumulate in the upper part of the core-mantle boundary,and become an important component of the mantle plume generated at the core-mantle boundary.Secondly, a series of high- temperature and high-pressure petrological experiments have obtained a series of high- temperature and high- pressure mineral assemblages that vary with depth, which are considered to represent the mineral assemblages of Earth’s mantle transition zone and lower mantle,and even the water-bearing mineral assemblages at the core mantle boundary. In addition, computer simulation shows that deep subduction of cold oceanic lithosphere is feasible. Most importantly,many high-pressure minerals from the mantle transition zone or even the lower mantle have been discovered in nature. It has been proved that some of them were derived from deep subducted oceanic crust,and they record the history of subducted oceanic crust. For example, evidence of mineral inclusions found in kimberlitic “super- deep” diamonds in Brazil, South Africa and Canada, as well as isotopic evidence of early subducted crustal rocks recorded in oceanic island basalts and intraplate basalts suggest that early deep subducted materials can be brought from deep to surface through mantle plume activities.Recent discovered ophiolite-hosted diamond may provide a new example.The carbon isotope and inclusion studies of ophiolite- hosted diamond indicate that they are originated from the early subducted crustal materials.Thus,ophiolite can be taken as a new window for the study of deep recycling of subducted materials.This paper reviews the current progress in the Earth’s deep material cycling and emphasize importance of deep cycling of subduction material in the study of geodynamics.