In this letter, a method, patch antenna and microstrip method (PAMM), for identifying the surface-wave band-gap of electromagnetic band-gap (EBG) structures is introduced. The key idea of PAMM is that a patch antenna, fed by a microstrip line, is served for a radiator and an open-end microstrip line with characteristic impedance of 50 Omega, is employed as a detector for the electromagnetic field along the substrate. Several rows of EBG structures are inserted between the detector and the radiator. The band-gap range of surface-wave can be identified by measuring the transmission through the detector and the radiator. Simulation results show that the transmission coefficient with EBG presence is lower than that of case without EBG absence above 10 dB. On the other hand, the gain of the antenna increases 1.9 dB when four rows of EBG are present. The results verify that the propagation of surface-wave is suppressed and the method is effective.