In this study, we present an analytical approach which uses an automated pre-concentration device(seaFAST) with accurate volume loading and in-line pH buffering of the sample prior to loading onto the chelating resin (NOBIAS chelate-PA1) and subsequent simultaneous analysis of copper (Cu), lead (Pb), zinc (Zn) and cadmium (Cd) by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The available system extracts the trace metals from the seawater onto a chelation resin column, when the seawater sample pH<2, mixed with the buffer solution of ammonium acetate with pH (6.0±0.1) in a certain volume ratio (13:2~13:5). And the resin can be washed with the buffer solution of ammonium acetate no less than 800μL, which can effectively remove alkali metals, alkaline-earth metals, anions, etc. The four target elements can achieve high recovery at the same time when the resin eluted by 10% nitric acid which is no less than 600 μL at the rate of 200 μL/min. The detection limits of this method were 0.014 μg/L(Cu), 0.002 μg/L(Pb), 0.049 μg/L(Zn), 0.001 μg/L(Cd).The analytical technique has advantages of high automation and small volume of reagents and samples. There is no significant difference of the analytical results, which is the trace metals in seawater of Changjiang Estuary and its adjacent areas, between this method and the one of the specification for marine monitoring. It shows that this method is stable and not affected by salinity. It is suitable for the analysis of trace metals in the estuary and its adjacent areas.