Abstract: Objective To observe the effect of 2450 MHz microwave on the white blood cells (WBC) and haematogenous of granulocytic series of mice.Methods The whole body of BALB/c mice were exposure to 2450 MHz power density (10 mW/cm²) microwave, and the mice were killed at different times after exposure, to determine the changes of spleen/body ratio, peripheral blood WBC, number of marrow nucleus cells, cell cycle and form ability of GM-CFU (granule and macrophage-clone forming unit).Results The number of peripheral blood WBC increased at first and then reduced with the exposure time prolonged. Number of marrow nucleus cells kept decreasing after microwave exposure, otherwise, form ability of GM-CFU of marrow cells increased. Exposure to 2450 MHz 10 mV/cm²microwave might speed up marrow nucleus cell passed from G₁ period to G₂ and S periods.Conclusion Low frequency of 2450 MHz microwave exposure has significant stimulate function on granule cell system, but with the time prolong, number of nucleus cells decreased.

Key words: microwave, white blood cell, haematogenous, cell cycle