In the small sample problem, the data distribution is unknown and the traditional methods are complicated. In order to address the small sample problem, it combines the grey accumulated generating operation with the GM (1, 1) model in this article. This method is applied in the non-diffracting beam triangulation measurement system and compared with the original methods. The result shows that the novel method can remove the abnormal data reasonably and quickly. In the large sample problem, the new method can gain the same result as the statistical methods. In the small sample problem, the proposed method can overcome the shortages of the existing evaluation methods and can be one of complements for the original methods.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.