The agar-C3N4 hybrid hydrogel photocatalysts with 3 dimension (3D) network structure have been prepared via thermoreversible phase transition of agar. The hybrid hydrogels show high efficient pollutants removal ability by synergistic effect of adsorption and photocatalytic degradation. The removal ability of phenol and methylene blue (MB) by hybrid hydrogel is about 1.3 and 4.5 times of pure g-C3N4 respectively. The pollution can be degraded continuously via agar-C3N4 hybrid hydrogels photocatalysts without separation. (C) 2015 Elsevier B.V. All rights reserved.