Abstract: Acid α-mphthyl esiere.se (ANAE),a cytoplasmic marker,was used to identify the T lymphocytes and their subpopulations in peripheral blood of mice infected with Trichinella spiralis,and Dot-ELISA was used to identify the serum IgG antibody of the infected mice. The results showed that T lymphocytes increased on the d3 after infection,reaching the peak on d14,and then remainel in number greater than normal up to d77.The spotted granular ANAE positive cells (Help T cells,Th) deereased and the scattered granular ANAE positive cells (Suppresor T cells,Ts) increased,leading to a drop of the Th/Ts ratio.The reduction in host immune function during T.spiralis infection might be related to the drop of Th/Ts ratio.At the same time,the serum IgG antibody increased on d7 after infection,reaching the peak on d28,and remained higher up to d140.Tl:e results indicated that the host's cellular immunological level was lower while the host's IgG antibody level was higher during T.spiralis infection.