The same batches of hydrocortisone injection were irradiated by 60Co γ-rays with different absorbed doses of 2, 4, 8, 16, 26, and 34 kGy, respectively. The color and clarity of hydrocortisone injection were inspected and the content of hydrocortisone was analyzed by HPLC. The results show that the injection content decreases with the increment of absorbed doses (p<0.01), and it is out of the control quality when the absorbed dose more than 2 kGy. Moreover the color becomes yellow and then is transferred transparent. The hydrocortisone injection is unstable to radiation as it will generate some colored and less soluble substances under radiation environment.Cited