The invention discloses a measuring system and measuring method of aerosol scattering and moisture absorbing growth factors. The measuring system comprises a drying pipe, a first nephelometer, a second nephelometer, a humidification pipe, a first three-way valve, a second three-way valve, a first two-way valve, a second two-way valve, a first water bath, a second water bath and a computer. According to the measuring system, an outer-layer casing pipe and an inner-layer semipermeable membrane pipe are adopted to form the humidification pipe, water in the humidification pipe and the water baths form a closed cycle, the water temperature is controlled by the water baths, and the highest relative humidity of a humidified aerosol sample can reach 95%; the two water baths are adopted to participate in humidification efficiency controlling, when the system runs, the working modes of the two water baths are staggered and are the heating mode and the refrigerating mode respectively, and therefore the time resolution can be increased by one time; in addition, in the whole circle period, the system is always in a relative humidity increasing period, and therefore effective data outputting is guaranteed.