In this work, a novel up-conversion luminescence agent (Er3+:Y3Al5O12) was synthesized by sol-gel method and then for visible-light photocatalytic hydrogen evolution a corresponding visible-light photocatalyst, platinum supported titanium dioxide nanocomposites coating up-conversion luminescence agent (Er3+:Y3Al5O12/Pt-TiO2 nanocomposite particles), was successfully prepared by sol-gel and calcination methods. Er3+:Y3Al5O12, Pt-TiO2 and Er3+:Y3Al5O12/Pt-TiO2 were all characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy (EDX). The visible-light photocatalytic activity of Er3+:Y3Al5O12/Pt-TiO2 nanocomposites was examined through photocatalytic hydrogen evolution from methanol splitting under visible-light irradiation. The influence factors such as Er3+:Y3Al5O12 and Pt-TiO2 mole ratio, heat-treated temperature and heattreated time on the visible-light photocatalytic hydrogen evolution activity of Er3+:Y3Al5O12/Pt-TiO2 nanocomposites were also studied. Particularly, Er3+:Y3Al5O12/Pt-TiO2 nanocomposites with 1.5:1.0 M ratio heat-treated at 500 degrees C for 60 min showed the highest visible-light photocatalytic activity in hydrogen evolution from methanol splitting. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.