Abstract: An improved algorithm based on the traditional angle zbuffer（AZB)algorithm was presented for easy programming，effectively reducing its complexity，improving speed of operation.In twodimensional plane，this algorithm could partition the radiation space of radiation sources and equivalent radiation sources，find out faces and edges obscured by polyhedron itself and others，sort polyhedrons before and after，thus the threedimensional ray tracing was achieved.The algorithm was applied to a mobile communications base station，and the calculation program was written based on matlab.The error between the field strength calculation result and the actual measurement result is less than 5 dB and in good agreement，which shows that the search of the propagation path is perfect，without missing. The software can be applied to the electromagnetic environment evaluation.