A control method of radon progeny state parameters in small radon chamber was established based on behavior theory of airborne radon progeny and aerosol particle.The state parameters including radon and radon progeny concentration,equilibrium factor and unattached fraction were controlled steadily in small radon chamber by adjusting the total ventilation rate of radon chamber and aerosol particle number concentration.Physical model of the control method was established,and the behavior parameters of radon p...