Abstract: The corrosion and stress corrosion behavior of 304L stainless steel in liquid ammonia was investigated through immersion tests and slow strain rate tests. The results indicate that the corrosion rate of 304L stainless steel in liquid ammonia was very low. As the test pressure increased from 1 MPa to 4 MPa, the corrosion rate of the specimens rose from 0.0065 mm/a to 0.0115 mm/a. When the test pressure was 1 MPa and 2 MPa, the stress corrosion susceptibility index of 304L stainless steel ranged from 25% to 35%, indicating a potential risk of stress corrosion cracking. When the test pressure was 4 MPa, the stress corrosion susceptibility index of 304L stainless steel reached 48.3%, which was relatively high. As the test pressure increased, both the corrosion rate and stress corrosion susceptibility of 304L stainless steel in liquid ammonia increased.