To calibrate the accuracy of humidity measuring equipment, the principle of shunt was used to design humidity generator, the PC control system was designed combining the LabVIEW software.In the calibration system, the lower machine was used to realize humidity occurs, measure and analysis of temperature, humidity, flow signals and etc; the virtual instrument software was used to realized the functions of humidity control, serial communication, automatic generation of calibration reports and other interfaces and functional design. The system has been applied to the actual humidity calibration equipment. The results show this equipment can occur humidity from 20% RH to 90% RH, the accuracy is within 2% RH. The system reduces the workload of parity staff and improves the degree of automation.