In this work, effect of big paddy hermetic tent (BPHT) modified atmosphere packaging (MAP) of 0.5mm PE and traditional MAP using 0.05mmPE on free fatty acid property were investigated. The results showed that BPHT, which were charged 5% O2 and 5% CO2, was the optimal storage condition to preserve rice grain fresh. Little O2 decreasing and CO2 increasing were generated in traditional MAP other than fruits and vegetables, because grain respiration rate were low relatively. After five moths storage of rice grain, BPHT storage inhibited the free fatty acid content increasing and lox enzyme activity. BPHT storage with atmosphere charging at storage beginning was the distinctly energy conservation storage method for grains.