Abstract: In this paper, in order to partially resolve the problem of over-nutrition of tobacco at the late growth stages, the field plot experiment in situ incubation and the indoor experiment in the aerobic incubation were carried out to study the effects of different intercropping times of Amaranth and rye grass on decreasing nitrogen mineralization at the late growth stages. The results show that the two non leguminous plants, Amaranth and rye grass, could absorb soil nutrients and compete with flue-cured tobacco when they are intercropped. In the field plot experiment, the mineralization amounts of intercropping Amaranth from the 35th days, Amaranth from the 49th days and rye grass from the 49th days are decreased by 65.81%, 54.57% and 65.90%, and the effects are significant different from those of the control. In the indoor experiment, the mineralization amount of intercropping Amaranth from the 49th days is decreased significantly during 49-77 d, and this could cause less nitrogen absorption. The intercropping rye grass and Amaranth could both absorb over-nutrition of soil with tobacco planted, and the effects of intercropping rye grass and Amaranth from the 49th days are the best.