This paper presents ESPI system for the measurement of thermal expansion coefficient of STS430 up to 1,000 ℃, Existing methods, strain gauge and moire have the limitation of contact to object and do not supply the coefficient up to 800 ℃. There needs to measure the data up to 800 ℃, because heat resistant materials have high melting temperature up to 1,000 ℃. In previous studies related to thermal strain analysis, the quantitative results have not reported by ESPI at high temperature, yet. In-plane ESPI and vacuum chamber for the reduction of air turbulence and oxidation are designed for the measurement of the coefficient up to 1,000 ℃ and speckle correlation fringe pattern images are processed by commercial image filtering tool-smoothing, thinning and enhancement- to obtain quantitative results, which is compared with references data. The comparison shows two data are agreed within 4.1 % blow 600 ℃ however, there is some difference up to 600 ℃. Also, the incremental ratio of the coefficient is changed up to 800 ℃. The reason is the phase transformation of STS430 probably begins at 800 ℃.
