Disclosed is a method for evaluating an irradiation angle of a beam, including a step of sampling the irradiation angle of the beam, wherein the irradiation angle of the beam is defined as being the direction of the vector of the irradiation point of the beam to the pre-set point of the tumor； and a step of calculating the track of the beam passing through the organs, wherein it is determined whether the tumor is fully covered within the effective treatment depth, and if so, entering the steps of calculating the evaluation coefficient, recording the irradiation conditions and calculating the results, and returning to the step of sampling the irradiation angle of the beam； and if not, entering the step of giving the worst evaluation coefficient and returning to the step of sampling the irradiation angle of the beam.
