The study on ash content of crude fuel in coal seams seems to be extre mely important in quantitative interpretation of digital logging in the coalfield. In this paper, the volume model nonlinear computation is used to predict ash content of crude fuel in coal seams with medium-high resistance in No. 1 Shaping opencut coal mine of the Hedong coal field in Shanxi province and the suburban mine field of the Yongcheng coal field in Henan province, with the mean square error being respectively 2.65% and 1.78%.