The invention belongs to the technical field of nuclear radiation protection and provides an iodine sampler and an operating method thereof. The iodine sampler comprises a shell, an iodine box, a first pipeline, a first valve, a first flowmeter, a second pipeline, a second valve, a second flowmeter and a blower. The top of the shell is opened and communicated with the outer atmosphere. Filter paper used for acquisition of aerosol is arranged at the opening of the shell. One end of the first pipeline is communicated with the blower, and the other end of the first pipeline extends into the shell. The first pipeline is provided with the first valve, and the first flowmeter is arranged at the first valve. One end of the second pipeline is communicated with the blower, and the other end of thesecond pipeline extends into the shell to be connected to the iodine box. The second pipeline is provided with the second valve, and the second flowmeter is arranged at the second valve. By regulatingopening of the first and second valves, the flow of a gas flowing through the iodine box accords with a set value. According to the invention, measurement precision can be effectively raised.