Abstract: Mining design generally needs to establish a block model or a three-dimensional solid model for calculating the irregular geometrical volume. It is found that in practical applications the two models have their own disadvantages. The block model has the problem of computation error, i. e. discretization accuracy, and the three-dimensional model has the disadvantages of long time consuming and instability. In order to solve these problems existing in the two models, this paper proposed a new semi-continuous and semidiscrete model and subsequently provided the model algorithm and practical cases. Research results illustrate that the proposed semicontinuous and semi-discrete model has the advantages of high computing speed, low error, and calculation stability, so it is a high efficiency method for mining design.