Fast and accurate deformation measuring techniques have promising potential for monitoring of high-temperature piping and other machinery in the energy sector, such as thermal, stream, or nuclear power plant. Optics-based non-intrusive and real-time monitoring systems are critical for preventing high temperature steam leaks, unexpected accidents, explosions, and other failures that can have catastrophic consequences for the power supply, worker, and the public. In this study, a dynamic thermal deformation measurement technique utilizing the sampling moiré method is developed for large-scale high temperature piping in the thermal power plant. To endure the high temperature nearly 300°C of the piping, several ferrite magnets with 100 x 100 mm are used to attach to the interested locations of the high temperature piping. In each ferrite magnet, a regularly two-dimensional binary grating pattern with 15 mm pitch was sprayed onto the surface, and the magnetic grating was used as the reference grating to analyze the displacement distribution by the sampling moiré method. Experimental results showed that our measurement technique is possible for structural evaluation of high temperature large-scale infrastructures.