Abstract: Salt spray tests are performed on 3 steel types with silimar properties，i.e.，Cr－Ni－Cu series grade Ⅰa steel，Q345B steel and X52Q steel.The corrosion resistance of grade Ⅰa weathering steel is then analyzed by observing the changing of the corroded surfaces and comparing the differences between the weights before and after the tests.The tests show the following results.The corrosions of different steel types at 48，120 and 168 hours have no significant difference，but the rust layer of gradeⅠa steel presented after descaling is a little more compact than that of Q345B steel and X52Q steel.The resistances of these types of steels against salt-spray corrosion in short time periods show that X52Q∧Ⅰa∧Q345B，different from the values calculated using atmospheric corrosion resistance indexes，which might be the result of the influence of testing time，grain size，alloy elements and microstructure.