Environmental mercury pollution poses a serious threat to public health and ecosystems, underscoring the value of rapid and accurate on-site mercury measurement technologies. Therefore, a portable mercury analyzer was developed with capillary point discharge for excitation and cold vapor generation for sample introduction. A limit of detection (LOD) of 0.23 μg L−1 for mercury was achieved, relative standard deviations below 5 % were maintained in a 10-hour testing period. This method was successfully used for mercury determination of spiked water samples, fish meat, and laboratory wastewater. Powered by several power banks, it can be used to monitor mercury levels in water samples continuously over a working day. Compared with traditional technology, this one greatly reduces the size of the instrument, the consumption of working gas, and the construction cost, making it suitable for rapid field analysis of many types of samples for trace mercury.