In view of the vacuum insulation panel (VIP) with silica or glass fiber， we can measure the inner pressure to judge its quality. Based on the negative pressure expansion method (i.e.， inverse vacuum method)， this paper develops an instrument to measure VIP′s inner pressure quickly and efficiently， so as to identify whether the VIP is qualified or not. Compared the measuring results with the theoretical value， it is proved that the accuracy of instrument is high and its error can be controlled within 1%. Then， for the VIP with glass fiber， the effect of different diameter sizes of suckers on inner pressure measuring is studied， and test result shows that only the sucker with small diameter size can measure the inner pressure.Finally， using the MATLAB linear fitting module， the function relationship of inner pressure and thermal conductivity of two kinds of VIP is discussed， which can guide the high-quality producing of VIP theoretically.