Objective: To study correlation between boiling point and vacuum in vacuum water extraction technology

and compare effects of different medicinal dosage on the vacuum and the average molar heat of vaporization. Method: Theoretical calculation and decompression test determination were used to obtain the vacuum at different boiling point.Then the saturated vapor pressure value and the average molar heat of vaporization in this system were calculated. Result: There are changes between the measured and theoretical values of vacuum with the pure solvent;After added medicinal materials

the measured values of vacuum were lower than the measured values of the pure solvent

the measured values of the average molar heat of vaporization were lower than the values of the pure solvent.Effects of medicinal dosage on the measured value of vacuum had no significant. Conclusion: There was no substantive impact on vacuum control in water vacuum extraction process by adding Chinese medicines.