The QAl-7 aluminum bronze powder is cladded on the Q235 carbon steel surface by laser cladding technique in order to improve the surface performances of marine steels. Microstructure and copper contamination phenomenon near the fusion line are also studied. The research results show that the aluminum bronze coating undergoes liquid-phase separation and decomposition of oversaturated solid solution. The microstructure mainly consists of copper-rich phase (Cu3Al, Cu9Al4) and iron-rich phase (AlFe3, AlFe). The liquid copper alloy in the molten pool wets and extends along the austenite grain boundary of the substrates. There occurs the copper contamination phenomenon in the heat-affected zone. The contamination depth of copper alloy is related to the width of fusion zone. The fusion zone is wider, the copper contamination is deeper. Thus, the depth of copper contamination can be controlled just via the reduction of the width of fusion zone by controlling laser parameters. The copper contamination cracks are further suppressed.