Abstract: The reliable measurement of radon exhalation rate is critical in environmental radon pollution regulation. The activated carbon adsorption method and electrostatic collection method are commonly used to measure radon exhalation rate. Only when the range of radon exhalation rate variation is relatively small and environment condition is relatively stable, the activated carbon adsorption method can be applied. Although the electrostatic collection method can realize fast measurement, the present electrostatic collection type manometer such as RAD7 still needs to conduct data correction to obtain the value of radon exhalation rate. In order to achieve the reliable measurement of the radon exhalation rate, University of South China developed a portable automatic measuring monitor of radon exhalation rate in accordance with methods of collecting radon through accumulation and measuring radon by collecting static. This measuring monitor can sample gas without drying tube, which reduces the influence of desiccant on radon exhalation rate of dielectric surface in radon collecting cover in natural environment, and it can accurately measure the instantaneous radon concentration without needing personal computer to conduct linear fitting and data processing. After its internal microprocessor converts linear fitting into algebraic operation, it can automatically calculate the radon exhalation rate based on measured radon concentration. The experiment indicates that the relative deviation is less than 5%. The directly obtained radon exhalation rate after measuring satisfies the requirement of field radon exhalation rate measurement.