Nowadays, reinforced concrete components are widely used in coastal and offshore structural engineering. In harsh environments with seawater corrosion, dry-wet alternation, and extended cyclic loads, steel bar corrosion eventually leads to serious structural damage. In this paper, fatigue tests of six reinforced concrete test beams under corrosion and cyclic loading were carried out. Two kinds of cyclic loading amplitudes (2%-40% P_u and 2%-60% P_u) were designed, and fatigue failures in the atmospheric environment, freshwater environment, and corrosional seawater environment were studied. Mechanical properties and damage to reinforced concrete beams under three kinds of environments and cyclic loads, based on the evolution law of stiffness, were further explored. Failure mode, crack width, deflection development, and fatigue life were analyzed. Study results showed that under the combined action of corrosion and cyclic load, the corrosional solution did not significantly affect the internal reinforcement of the beam in the short term. Durability of the test beam as reduced by 42% within certain cyclic times, and durability of the two test beams were reduced by 54% and 37% when the upper limit of cyclic load was 0.6 P_u.