Eighty mice aged 3 weeks were divided into electromagnetic pulse (EMP) exposure and sham exposure groups, with 40 mice in each group. The EMP group was exposed to electromagnetic pulses for 14 days with a daily dose of 400 pulses at 200 kV/m. On Day 1, 7, 14 and 28 after exposure, the mice were weighed and killed. The mouse testis were observed and the testis indexes were calculated. Serum growth hormone (GH), testosterone (T) and gonadotropin-releasing hormone (GnRH) were measured by radiommunoassay. Hematoxylin-eosin (HE) staining combined with decussation imaging analysis was carried out to measure the diameter of seminiferous tubules. The results show that the body weights of the exposure group are significantly lower than those in shame-exposure group on Day 10 of the EMP exposure and on Day 4 after the EMP exposure. After exposure, the testis weights of exposure group are significantly lower than those of sham-exposure group. Compared with the testis indexes of the control group, those of exposure group decline more obviously. The contents of serum GH, T and GnRH significantly declined. And the seminiferous tubules’ diameters of exposure group also decline. These suggest that EMP exposure can inhibit the development of reproduction in growing male mice, such as reducing the contents of sex hormone, the testis indexes and the diameters of seminiferous tubules.Cited