Conjugated polymers (CPs) have been demonstrated to be excellent solar energy conversion materials, however, it is considered that pure CPs are not able to photocatalyze water splitting because of the fast recombination of photogenerated charge carriers. Here, we found polythiophene (PTh) nanofibrous structure can have a decent photocatalytic activity (2.19 mmol h(-1) g(-1)) and stability in ascorbic acid aqueous solution under visible light irradiation. Furthermore, PTh synthesized at high temperature will introduce structure defects, such as, alpha-beta' coupling and end groups, which are beneficial to the charge separation. In addition, PTh synthesized at low temperature has long polymer chain and ordered arrangement of chain, which enhanced the light adsorption. Considering both light adsorption and charge separation, PTh compound nanostructure was rationally designed, PTh synthesized at low temperature as core to obtain good light adsorption and PTh prepared at high temperature as sheath to form more structure defects to promote charge separation. This PTh compound nanostructure exhibit higher photocatalytic H-2 production performance (2.8 mmol h(-1) g(-1)). Our finding may open a door for conjugated polymer for photocatalyst. (C) 2017 Elsevier B.V. All rights reserved.