At the forced air cooling stage in normalizing process of heavy steel castings, the nonuniform cooling might result in thermal and phase transformation stresses, which might cause the distortion, especially for the heavy yet thin blade castings. Dynamical measurement of the distortion of castings during heat treatment process will be significant for understanding the mechanism of distortion and then taking the control measures in productions. In this paper, a novel measuring method, fixed direction method, was proposed, which could three-dimensionally and dynamically measure the distortion of castings without index points at high temperature, and the corresponding analysis method was established. The method was employed to measure the distortion of a hydro blade casting at the forced cooling stage in normalizing process, and the dynamical distortion behavior in three dimensions of the blade casting was obtained. And the measurement error of blade casting was analyzed. The results show that under the conditions of no index points and high temperature, the three-dimensional distortion of castings could be dynamically measured through the fixed direction method. © Copyright.