The mechanical behavior of tungsten under high temperature conditions has great significance and important reference value in fusion reactor engineering as tungsten is currently the first choice of plasma facing materials of the divertor and the first walls.. In this paper, the thermal expansion deformation of tungsten material in temperature range of 25℃ and 2000℃ is measured by a digital image correlation (DIC) equipment based on a vacuum high-heat-flux comprehensive experimental platform, in which a special speckle preparation technique using tantalum carbide powder is developed and two kinds of DIC light path arrangements with external and self-radiation blue light source respectively are designed and realized. The measurement results are in good agreement with those calculated by an empirical correlation equation provided from material handbook (the general error is less than 1%), validating the feasibility and accuracy of adopted measuring techniques. The techniques developed in present investigation lay good foundation for further development of measurement technology of materials under high heat flux shock in fusion engineering.