In order to reduce energy consumption and the concomitant green house gases (GHG) emission of networks, the issue of routing with lower carbon emission in IP over wavelength division m ultiplexing (WDM) networks is inve stigated in this paper.A hold-time aware green routing (HTAGR) algorithm based on layered graph model is proposed, with an integrated consideration of holding-time of traffic and the hybrid usage of renewable energy and non-renew able energy.The proposed algorithm dynamically adjusts the weights of links according to the solar energy supply of nodes and the energy consumption of nodes and fiber links.And it encourages to choose the path with the least additional traditional energy consumption during the holding-time of traffic.The simulation results show that the HTAGR algorithm ca n not only maintain a low blocking probability,but also reduce traditional energy consumption and carbon emission by encouraging to use more renewable energy,compared with other traditional energy-saving algorithms .