Intensity forecast errors are analyzed according to the official forecasts from the Central Meteorological Observatory (CMO) of China Meteorological Administration (CMA) for typhoons in the western North Pacific during 2001-2012. It is shown that no significant improvement can be observed during the 12 years with undulating annual mean errors. The forecast errors are relatively small for steady intensity change process, but large for rapid intensity change process. There is a high probability for the forecasts to be stronger (weaker) than the observations at the leading time of 24, 96 and 120 h (48 and 72 h). It should be noted that the forecast errors are larger at the northeastern part of the South China Sea than other locations. The probability of the forecast intensity being stronger than the observations in 120 h is increased with the increase of typhoon intensity. The threshold error values of 70% accumulated probability are calculated for typhoons in different intensity and moving speed categories and a probability intensity forecast scheme is proposed to provide a guidance with an estimation of the forecast errors.