Harsh environmental conditions, including pressure and temperature extremes, vibration, shock, radiation, chemistry (acids, bases), biological domains, and corrosion attacks, pose a significant challenge for conventional sensing devices. Most sensing elements on the market cannot survive in harsh environments. However, accurate monitoring of pressure and temperature in extreme environments is critical to several modern industrial segments, including the manufacturing, automotive, aerospace, gas turbine, nuclear power, gas and oil exploration, and petrochemical control sectors. As a step toward resolving this challenge, we used a new piezoelectric material which can keep its piezoelectricity at 1400 C as a sensing element. In addition, we discovered a special cut angle that can enable the dual-mode sensing capability; one mode is used to detect high temperature and the other to detect pressure based on force frequency effect (Fig. 1), so that a high-accuracy measurement of temperature and pressure can be performed with a single sensing element. Furthermore, we used a thermoelectric module and vibration energy-harvesting module to harvest the energy from the harsh environment to realize the complete self-powered piezoelectric resonant sensor for harsh environment sensing.