This study was to evaluate the effect of a Chinese genetic engineering product of rhG-CSF (Lishengsu) on leukopenia induced by chemoradiotherapy in patients with malignant solid tumors. One hundred and forty cases of leukopenia following chemoradiotherapy for malignant tumors were treated with Lishengsu. When the total leukocyte counts (WBC) less than 3.0 x 10(9)/L or the absolute neutrophil count (ANC) less than 2.0 x 10(9)/L, Lishengsu was given 75 micro g/day subantaneously and the administration was stopped when the WBC counts rose up to 4.0 x 10(9)/L or higher, or the ANC counts reached 2.5 x 10(9)/L or more. The results showed that peripheral leukocyte counts in all patients following the treatment with Lishengsu were recovered and the average time of its administration was 4.8 days. The rate of its efficaciousness was 96.4%. It is concluded that Lishengsu could elevate nadirs of leukopenia and significantly shortened time period of leukopenia below 4.0 x 10(9)/L with acceptable mild side effects, decrease complications of infection so that the chinese product of rhG-CSF facilitates chemoradiotherapy significantly.