W/ZrC cermets were fabricated by DCP method. The evolution laws of composition and microstructure of W/ZrC cermets in different ultra high temperature environment were investigated. Results show that the heat-treated microstructure of W/ZrC cermets is still comprised of metal tungsten and ceramic zirconium carbide. With an accretion of temperature, the weight loss first increases and then decreases, attaining a maximum 2.05 wt.% at 2200 ℃, and the open porosity increases constantly, reaching to 9.29 vol.% at 2600 ℃. On the materials surface, the residual Cu melt and volatilize firstly, and then residual Zr, a few ZrC vaporizing at 2600 ℃. While inside the materials, the WC phases disappear after heat treatment at 1800 ℃, also the residual Zr-Cu alloy phases and W2C phases at 2200 ℃, when heat treated at 2600 ℃, only W phases and ZrC phases reserve in W/ZrC cermets. Moreover, more W atoms diffuse into the ZrC phases along with the temperature increases, leading to lattice constants of ZrC decrease, and the orbicular W phases change to be ruleless long strip, also the quantity and volume fraction of W phases reduce, and lots of obturators form contrarily. The melting loss of remanent Zr-Cu alloy and diffusion of W atoms are important reasons for arosing composition and mircrostructure changes of W/ZrC cermets in ultra-high temperature.