We perform an amplitude analysis on photon-photon scattering into pion and kaon pairs below 1.5 GeV. To get a model independent amplitude as possible, we impose the basic constraints required by analyticity, unitarity, and crossing-symmetry. To fix the relative hadronic amplitudes, we include the latest hadronic pipi, KK scattering amplitudes given by dispersive analysis, supplemented in the KK threshold region by the recent Dalitz plot analysis from BaBar. With these hadronic amplitudes and applying Final State Interaction theorem, we give an overall fit of gamma gamma-->pi pi datasets, including the high statistics neutral pion data of Belle. A region of solutions are found and what should be emphasized, the relatively poor integrated cross-section data on gamma gamma -->K K narrows the patch of solutions to essentially a single form. Finally we present the photon couplings of scalars and tensors appear in these processes, which are quite helpful to distinguish their structure.