Abstract: According to the principle of anchor supporting a mechanical model of implicit cylindric anchor bar element is presented. This cylindric element is composed of anchor bar and solidified surrounding rock. Hiding in surrounding rock, the implicit cylindric anchor bar element can be arranged arbitrarily after rock elements are divided. Therefore, it not only can be conveniently applied to analyse various scheme of anchor supporting without changing the network of rock elements, but also can effectively accelerate the computation rate. By analysing for engineering examples, we find that the calculating model reflect sufficiently the effect of anchor supporting for.underground opening.