Abstract: The experiment studied two flue-cured tobacco varieties (K326 and NC89)drought resistance with NH₄NO₃, NaNO₃, UREA and (NH₄)₂SO₄ applied, respectively, and the four nitrogen forms on biological characteristics and leaves yield.The result showed that at the same fertilizer level the positive effect of four nitrogen forms on tobacco grow th followed the order NH₄NO₃ > NO₃-N > NH₄-N > UREA, and NC89 grows well to NH₄⁺-N and UREA in the soil, compared to K326.By comparison of yield of tobacco leaves with the four nitrogen forms applied, and moisture metabolism, nitrogen metabolism, activity of root system, cell membrane diffusions and antioxidation induced system were studied, the results showed that the drought resistance of NC89 is higher than K326, fertilizer N forms on flue-cured tobacco drought resistance follow ed the order of NH₄NO₃ > NaNO₃ > UREA > (NH₄)₂SO₄, at the same soil moisture stress level.