This paper gives a method to measure in-plane strain of skew ruled surface shell by using Moire interferometry of sticking film method.The varied pitch gratings are made,principle of measurement,explanation of the Moire fringes of varied pitch gratings,establishment of formulas,analysis of precision,experimental technique, as well as the application to human maxillary complete denture base are discussed in this study.The good results verify that it is an applicable method.