Abstract: To study the deposition behavior of CaCO₃ scales on brass and copper surface, experimental tests were carried out at static state in 0.5 mmol/L CaCO₃ solution at 35 ℃, during which the scales obtained in different dipping durations were measured by weighing method and analyzed using scanning electron microscope. Results show that the scales are found to be more easily formed on copper surface than on brass surface under same conditions; higher pH value promotes not only the growth of scales, but also the formation of square aragonite and calcite, and the square aragonite will finally get recrystallized into the thermodynamically most stable phase (calcite); with the rise of pH value, both the homogenous nucleation in solution and the heterogeneous nucleation on metal surface increase, and the former one increases more than the latter one.