Abstract: Shock induced polarization (SIP) in PMMA laminas has been studied experimentally and theoretically. It is discovered that when a shock wave passes through the interfaces between layers of a PMMA lamina, some disturbance signals will occur on the SIP current curve. This has proved that the disturbance signal is due to the existence of narrow air layes among the PMMA laminas, which again exhibits a time probe effect indicating the time shock passing through. A theoretical analysis is proposed to interpret the interfacial signals. A new SIP gauge of laminate configuration is developed and other applications of the gange suggested.