A template matching method based on SNCC（self-normalized cross correlation）was proposed， which was based on the invariance of center rotation of centro-symmetric markers. This method had strong process adaptability to the non-linear scaling deformation caused by TFT process and the defocusing of markers. Through the contrast test of alignment mark and defocus alignment mark of TFT process deformation， it was verified that under this condition， the measurement results based on SNCC method had higher reliability than NCC （normalized cross correlation） and geometric template matching algorithm， and could meet the needs of accurate positioning and measurement at sub-pixel level of centrosymmetric marker. Compared with the traditional mark center positioning method， the proposed method could still obtain high reliability measurement results when the alignment mark produced process deformation or alignment defocusing.