Abstract: There are many disadvantages in conventional method，such as slow operating speed，poor stability and big error.According to these disadvantages，taking the Panjiantian iron mine as the research example，the DTM(digital terrain model)discrete model which lies between the discrete model and three dimensional solid model is established.Compared with the corresponding three dimensional solid model from the aspects of calculation accuracy，calculation speed，stability and visual display，the analysis results show that compared with the three dimensional solid model，the calculation error of the DTM discrete model is less than 1.00％and the calculation speed is also improved one order of magnitude.It is very stable and the accuracy can meet the requirements of accuracy；Besides that，the discretization error of the DTM discrete model is lower than the block model.The above analysis results further show that the DTM discrete model is worth being used as the effective method of ore-bearing rock measurement acceptance in open-pit mining，and also has some reference for the related calculation work of civil engineering and highway.

Key words: DTM discrete model, Three dimensional solid model, Block model, Tonnage of ores and rocks