In dark sector, there is a compelling possibility to have a light dark photon kinetic mixing with the standard model photon (or hypercharge). In this talk, I will briefly review a GeV scale dark photon search in the collider. After that, motivated from the GeV gamma ray excess in the Galactic center, I will consider a 10 GeV dark matter with a light dark force. The photon spectrum coming from the lepton and meson final states of dark matter annihilation can provide an explanation of the excess in the Galactic center. And I will talks about the constraints of this models from other experiments, in particular, focusing on the positron and electron measurement by AMS02.