In this work, bismerthiazol was firstly assayed by a fast and portable method employing protein-capping gold nanoculsters as probes. The luminescent intensity of the nanoclusters showed a correlative response towards bismerthiazol from 5 to 4000 μg/mL with a linear relation in the range of 5-100 μg/mL. As little as 5 μg/mL of bismerthiazol could be quantified. The high affinity of bismerthiazol to interact with the soybean protein-capped gold nanoclusters contributed to the excellent selectivity of this method over other common pesticides. The recoveries in several cabbage samples were 101-135%, indicating good performance in practical applications. By comparison to previous reported approaches, this method bears advantages including simple operation, fast response, visual readout and good selectivity.