Deterioration of concrete caused by freeze thaw cycles combined with chloride attack under flexural load was tested and analyzed. It is shown that for concrete under combined freeze thaw cycles and chloride attack, the generation and propagation of micro cracks caused by frost action degrades the pore structure of concrete, which accordingly accelerates chloride attack. On the other hand, the effect of chloride on the migration of pore solution and the saturation of concrete accelerates surface scaling and inner damage of concrete during freeze thaw action. Under combined flexural load, freeze thaw cycles and chloride attack, surface scaling is still the most serious problem, and the long term loading accelerates the deterioration of concrete and even increases the probability of rupture failure.