The electrochemical behaviour of direct strip casting (DSC) 304 stainless steel in 0.1 M H2SO4 and 0.01M HCl solutions was investigated. The DSC 304 stainless steel strips were produced by using either copper-alloy roller or 304 stainless steel roller. The difference in thermal conductivity of different roller materials resulted in a change in the surface microstructure of the DSC strips. Potentiodynamic polarization curves of the DSC 304 stainless steels produced were measured in 0.1M H2SO4 and 0.01M HCl solutions. The results showed that both alloys could passivate in the above solutions. In the HCl solution, the passive potential range of DSC 304 stainless steel with a higher ferrite content prepared by the copper roller was wider than that with a lower ferrite content. Furthermore, the addition of silicon could cause an expansion while the addition of titanium could lead to a shrinkage in the passive range in 0.01M HCl solution. Potential decay tests in 0.1M H2SO4 solutions showed that the reactivation time decreased as the ferrite content was increased.