The fatigue of concrete structures under the combined action of corrosive environment and repeated loads is becoming much severer. Cracks of reinforced concrete structures are easily induced by static and cyclic loading. These compromising transmission paths for corrosive medium will result in non-uniform corrosion of reinforcing steel bars, especially etch pits. At the bottom of hazardous etch pits, fatigue cracks will form and grow under dynamic loading until brittle fracture. We reviewed and analyzed the influence of concrete cracks on the fatigue properties of steel bars, the research progress of fatigue properties of pitting corroded steel bars and the fatigue of steel bars based on weak magnetic theory. Understanding the crack propagation behavior of pitting corroded steel bars is very essential for predicting the fatigue life of concrete structures inservice. Finally, a fatigue research method based on weak magnetic field theory is proposed to characterize the fatigue fracture behavior of corroded steel bars in real time. The corresponding characterization methods of equivalent crack propagation length and stress intensity factor variation of corroded steel bars may be novel for predicting the fatigue life of reinforced concrete structures inservice.