Gamma-ray personal dosimeters are important tools for the radiation protection for workers. However, the current calibration method based on standard reference radiation has low verification efficiency, large calibration workload, and requires remote inspection. To solve the above problems, this paper attempts to apply the minitype reference radiation to the calibration of gamma-ray personal dosimeters. The Monte Carlo method is used to simulate the dose distribution in the minitype reference radiation field, the influence of scattering rays which are caused by the device structure and dosimeters in the dose field. The results show that 1 Ci ¹³⁷Cs can provide a dose rate of 1.5 mSv/h for the point of test, and the relative standard deviation of the dose rate at the point of test is about 0.48%. When the thickness of the stage is 20 mm, the influence rate of scattered rays on the dose rate value at the minitype reference radiation inspection point is 3.27%, which is higher than the influence of the size of the dosimeter (1.62%) and the number of dosimeters (0.56%). This paper provides a theoretical basis for in situ calibration to calibrate gamma-ray personal dosimeters.