A High Temperature Gas-cooled Reactor (HTGR) is particularly attractive because of its capability of producing high temperature helium gas and its inherent safety characteristics. Hence, the High Temperature Engineering Test Reactor (HTTR) was successfully constructed at the Oarai Research Establishment of the Japan Atomic Energy Agency. The HTTR achieved the full power of 30MW and reactor outlet coolant temperature of about 850oC on December 7, 2001. After several operation cycles, the HTTR achieved the reactor outlet coolant temperature of 950oC on April 19, 2004. It is the highest coolant temperature outside reactor pressure vessel in the world. This is one of the major milestones in HTGR development of high temperature nuclear process heat application. Extensive tests are planned in the HTTR and a process heat application system will be coupled to the HTTR, where hydrogen will be produced directly from the nuclear energy. This paper gives an overview of the HTTR Project focusing on the latest results from the HTTR test and the future test plan using the HTTR.