Objective:To evaluate the clinical effectiveness and safety of the Chinese medicine (CM) Qixiong Zhongzi Decoction (芪芎种子汤,QZD) in the treatment of patients with idiopathic asthenozoospermia.Methods:A total number of 66 patients with idiopathic asthenozoospermia were included and randomly divided into treatment and control groups by SAS-generated code from January 2015 to August 2016,33 patients in each group.Patients in the treatment group were administered with 150 mL of QZD twice a day,whereas those in the control group were given 1 g of levocarnitine oral liquid twice a day.The two groups received the indicated medication for 12 weeks and were then followed up for 4 weeks.The primary outcome was sperm motility,and the secondary therapeutic indices were sperm volume,density,pregnancy probability,and CM syndrome score.The comparison between groups was carried out at 4,8 and 12 weeks,respectively.The safety was determined before and after treatment.Results:(1) Drop-off:5 cases (7.58％) were lost after treatment (2 from the treatment group and 3 from the control group).(2) Primary outcomes:after 8-and 12-week treatment,the progressive sperms in the two groups were significantly higher than the baseline (all P＜0.05);however,the treatment group showed greater improvement compared with the control group at 12-week treatment (22.7％± 9.0％ vs.14.1％± 8.8％,P＜0.05).The increasement of non-progressive grade sperms at both groups was observed at 8-and 12-week treatment with statistical difference (all P＜0.05),however,the treatment group showed remarkable improvement compared with the control group at 12-week treatment (38.7％ ± 14.1％ vs.26.2％± 15.4％,P＜0.05).(3) Secondary outcomes:no significant statistical differences were found in semen volume and density (4,8,and 12-week treatment) and pregnancy probability of patients\' wives (12-week treatment) between two groups (all P＞0.05),however,the CM syndrome score of the treatment group significantly declined compared with baseline level at each time points (all P＜0.05).(4) Safety:no obvious side reactions were found during the treatment in both groups.Conclusions:QZD could improve the progressive and non-progressive grade sperm in the treatment of idiopathic asthenozoospermia.It is safe with no obvious side effects.