Apparent recovery efficiency of applied N（REN）is an important parameter among nitrogen fertilizer utilization efficiency(NUE).As the REN value calculated by traditional subtraction was lower with a larger variation，the range of REN applications was limited.A reasonable method to calculate REN is especially important.After overviewed research process on REN over 50 years，3 research stages had been divided，and main innovations had been refined about REN calculating method.Using the longterm experiment research data，REN was calculated by conventional calculation method and some problems was presented.Two factors affected REN value，one was that the result was calculated by imbanlance soil nitrogen nutrient system.The other was that only the fertilization N and crop absorption N were considered to calculate the REN，without considering the residual soil N（or consumed soil N).Two calculation method of REN were completed in this study，one was for soil N nutrient balanced system：REN=（fertilizing crops N-decreasing returns factor×CK crop N）/ fertilizer N； The other one was for unbanlanced soil N nutrient system：REN =（fertilizing crops N-decreasing returns factor×CK crop N）/（fertilizer N+fertilization soil N consumption-CK soil N consumption).