In recent years, vertical axis wind turbine is widely used. However, when it is installed in cold regions icing and snow on blade surface will occur in winter. To simulate the situation of icing, computer simulations were carried out on a NACA0015 airfoil which is often used for vertical axis wind turbine. The computations were based on the N-S equation in 2D incompressible steady flow with using the DPM (Discrete Phase Model) to calculate icing. Under the different wind speeds and cold water discharges in cold air, the icing distributions on airfoil at 8 kinds of typical attack angles were calculated. The icing area on the leading edge and trailing edge of blade airfoil were also obtained. Based on these results, the factors affecting the icing on blade surface including wind speed, attack angle and cold water flow discharge were discussed. With the increasing of the flow discharge, the icing area ratio increases and ice accretions become more and more dense.