With people's increasing awareness of safety and health, the demands of protective clothing for electromagnetic radiation are gradually increased. The influences of clothing structural factors on protective performance for electromagnetic radiation are studied in this paper. The shielding effectiveness (SE) of fabrics has been tested according to the SJ20524-1995 standard. Meanwhile, according to the measured conditions of fabrics, a simulation model of testing fabric is established by the three-dimensional electromagnetic simulation software Ansoft HFSS to simulate the influences of clothing structural factors on the electromagnetic protective performance under the irradiation of electromagnetic waves at different frequencies. The impact of the length of clothing seams, the size and shape of clothing openings, and the change of clothing layers on the electromagnetic protective performance have been simulated and analyzed in detail. The results show that the simulation results are basically identical with the actual measurement results, and the model of testing fabrics can be applied for the researches on the protective performance for electromagnetic radiation. The study also shows that both seams and openings of clothing will reduce the shielding ability of clothing to electromagnetic radiation, and the change of clothing layers also affects the electromagnetic protective performance of clothing greatly. The results of this article can provide references for the design of electromagnetic shielding clothing, and effectively reduce the adverse effects of clothing structural factors on the protective performance of clothing.