Polythionine/AuNPs (PTh/AuNPs) composites were facilely synthesized through a one-pot synthesis method for the first time and used to modify glass carbon electrode (GCE) for constructing a highly sensitive and selective electrochemical sensor for dopamine (DA) assay. The prepared PTh/AuNPs was detailedly characterized by FTIR, UV-vis, TEM, EDX and AFM. Compared with pure polythionine, the prepared PTh/AuNPs exhibited more enhanced electron transfer property, higher electroactive areas and more efficiently electrocatalytical activity for DA. The prepared sensor could detect DA in the wide linear range from 7.5 to 320 nmol L-1 with a detection limit of 2.8 nmol L-1 (S/N = 3). The sensor could favorably avoid the interference of glucose, ascorbic acid, uric acid, ethanol and bovine serum albumin in the detecting process of DA. Furthermore, the sensor was successfully applied to detect DA in human serum with standard addition method. (C) 2015 Elsevier B.V. All rights reserved.