Abstract: It is discussed in this paper that methods of calculating dose field in a 60Co irradiation device with a pair of irradiation source frame by Microsoft excel. They are separately discussed that setting up a coordinate system in an irradiation field, calculating dose rate at a point in a Euler space by a single thread source, calculating dose rate at a point by all thread souces, and souce active at certain date. Applications at our irradiation center show that methods are correct.