Beef marbling level is the most important indicators in the evaluation of beef quality. The fractal dimension is closely related to marbling level. In this paper, the theory of fractal dimension is used to analyze beef marbling standards images in China and USA. After comparing several different dimension calculation method, the final method is improved box-counting dimension. Linear regression model of dimension calculation value with this method and marbling level is built. The model results are satisfactory through examination. For further use of samples, this model settles the foundation to establish the grade evaluation methods.