A dimensional measurement method with high accuracy for large size ceramic floor tiles based on the machine vision using single camera is presented. An optical system is designed, whose reflective light path consists of multiple mirrors. The images of four corners of the ceramic floor tiles are acquired by the single camera rather than the whole image, thus the asynchronous problem caused by multiple cameras acquiring the measured images is solved. Then the accuracy of measurement is improved. An algorithm for the tiles measurement is proposed based on boundary searching fitting and dynamic compensation. In such an algorithm, considering shift and rotation of the tiles in practical production, the dimension of diagonals and sidelines with high accuracy can be obtained by using the images of the four corners, which boundary searching of the measured images and dynamic compensation of measured dimension is performed. The measured standard deviation is less than 0.02 mm, and the repeatability approaches 0.06 mm when measuring dimension of diagonals and sidelines of 600 mm×600 mm and 800 mm×800 mm tiles. The experimental results show that the measurement system can be widely used in ceramic floor tiles manufacturers with high quality.