There are increasing interest in high temperature endurable sensor or device packaging solution for a set of wide ranging applications that include oil and gas production or deep sea exploration, advanced automotive application, aerospace, more electric aircraft initiative (MEA) or engine health management (EHM) systems, geothermal energy harvesting as well as other renewable energy industries. Besides high temperature endurable capability of the electronic device, heavy industries such as oil and gas down-hole drilling or exploration, deep sea or geological survey applications which require additional capability to endure high ambient pressure with target reliability requirement of up to 250°C and 30Kpsi. A unique packaging solution is therefore required to address all the challenges associated with extreme high temperature and high pressure (x-HTHP) endurable electronics continuous operation in harsh x-HTHP ambient environment. In this paper, we demonstrated a packaging solution for sensor device with high reliability under harsh condition with extreme high temperature and high pressure through reliability test and finite element analysis.