Abstract: A humidity generator that can be used as a second class regulator of standard humidity is developed. It simplifies the process in the demarcation of humidity instruments. The principle of double flow is introduced in the preparation of mixed gases. Microcomputer control system is embedded in the instrument to render automatic control in temperature, signal processing, data display and printing. Outgoing gas from the instrument is stable, in humidity and its value can be set at will, while the dew point temperature as well as relative humidity of the gas can be displayed and printed out. The instrument developed comes up to all indices of grade 2 standard humidity. Humidity supply and standard humidity instrument are integrated, and it can be made use of as a grade 2 standard in humidity by itself.