In the study a systematic finite strain measurement was made on a 50 km-wide section across the Altay orogen in the Fuyun region, with methods such as the dip-isogon of folds, three-dimensional strain of pebbles and S-C angle. Longitude and shear strain sections are constructed by these measurements. The results show that the shortening caused by the flattening of folds is up to 78% and the largest shear strain in faults is over 8. The three-dimensional strain and Flinn diagram analyses show that this area has experienced plane strain, and the faults have undergone simple shearing. Strain reconstruction for the shortening and shear deformation was accomplished with integration and reconstruction of normal distribution curves. It shows that the present 50 km-wide section was formed from a section with an original width of 266. 2 km by shortening and shearing.