A method for predicting a noise intensity emitted from a fan is provided. The method in accordance with the present invention provides data about the performance of the fan and a noise intensity corresponding to a shape of the fan and operating conditions so that the data are used in design and manufacturing of fans. The method comprises following steps for: analyzing a flow field around the fan on the basis of a fan shape and operating conditions; obtaining a noise source value of the fan from force data of blades at a given time in the analyzed flow field; and calculating a noise intensity from the noise source value.