Fatigue crack propagation tests in the Paris region were performed in order to get compressive loading effect on fatigue crack growth at negative stress ratio (R) in 2A12 aluminum alloy. The results of the tests showed that the effect of the compressive loading part of the applied stress cycle on fatigue crack growth rate da/dN in 2A12 aluminum alloy at negative stress ratio can not be omitted. The fatigue crack growth rate at R<0 was more than that at R>0 under the same range of stress intensity factor Kmax. The da/dN is the function of Kmax and stress ratio R. The promoting effect has an increase trend with the increase of the absolute value of the negative stress ratio R. Then a model involved compressive loading effect on fatigue crack propagation at negative stress was obtained. The model has been obtained good agreements with the experimental data.