Sphericity error assessment method for part based on minimum area

The invention discloses a sphericity error assessment method for a part based on the minimum area. The sphericity error assessment method includes the steps: a. coordinates of measurement points on a measured sphere are measured and obtained; b. primary iteration parameters of a ball are supplied; c. measurement points, the measured factors of which are contacted with an error tolerance zone, are inquired; d. translation direction vector of a tolerance zone is confirmed according to the relative positions of the measurement points; e. the change amount of the tolerance zone is calculated, and a next contact point is inquired; f. the measurement points which are contacted with the tolerance zone are inquired; g. the tolerance zone makes translation, iterative computations are conducted in sequence until judgment criterions are met, and sphericity error and the optimized parameters of the ball are output. By means of the sphericity error assessment method, the sphericity error and the optimized ball parameters on the minimum area are computed accurately.