Objective To explore the exercise induced immunity changes during incremental load training from the view of the expression of helper T cells (Th) mRNA. Methods Using the technique of real-time quantified PCR to observe T-helper-special cytokine mRNA of peripheral blood mononuclear cell dynamically in healthy young male who have been trained with incremental exercise for five weeks. Results There was no obvious change in IL-2 mRNA during five weeks training. Meanwhile IL-4 mRNA increased greatly in the second, third and fourth week. IFN-? mRNA as well as IFN-? mRNA/IL-4 mRNA increased remarkably in the third, fourth and fifth week . Conclusion The expression of T-helper1/ T-helper2 cytokine mRNA were up-regulated after five weeks and the subjects were gradually adapt to the increased load which indicated the enhancement of immunity function .