Objective To study the stress corrosion cracking (SCC) behavior of 304 stainless steel in simulated deep and shallow seawater environments. Methods The environment of a sea area in the South Sea was simulated by controlling different environmental factors, and potentiodynamic polarization, electrochemical impedance spectroscopy, slow strain rate test (SSRT) and superficial analysis technique using scanning electron microscope were applied for the research. Results 304 stainless steel exhibited a passivation behavior in the simulated seawater solution, and showed SCC susceptibility, besides, the crack propagation mode was transgranular cracking. The SCC mechanism in shallow sea was mainly controlled by anodic dissolution, while that in deep sea was controlled by hydrogen embrittlement. Conclusion Although 304 showed different SCC mechanisms in simulated deep sea and shallow sea, the SCC sensitivities were close and relatively low. So the use of 304 SS in simulated seawater environment was not limited by the depth of seawater.