Objective To compare the effect of monotherapies and combination therapy of endometrial curettage and intrauterine perfusion of granulocyte colony-stimulating factor（G-CSF） on pregnancy outcomes after in vitro fertilization and embryo transfer/intracytoplasmic sperm injection（IVF-ET/ICSI） in patients with thin endometrium（TE）. Methods A total of 204 patients with TE who underwent IVF-ET/ICSI in the Reproductive Medicine Center of the 940 Hospital of Joint Logistic Support Force of Chinese People’s Liberation Army from February 2018 to June 2023 were collected. The patients who did not receive special treatment before transplantation were included in control group（group A，52 patients），those who underwent endometrial curettage in curettage group（group B，60 patients），those who underwent intrauterine perfusion of G-CSF in perfusion group（group C，48 patients），and those who underwent endometrial curettage combined with intrauterine perfusion in combination therapy group（group D，44 patients）. The general information，clinical data，embryo transfer，endometrial condition at the time of transfer，embryo implantation rate，clinical pregnancy rate，biochemical pregnancy rate，early miscarriage rate，multiple pregnancy rate，preterm birth rate，and live birth rate were compared between the control group and the treatment groups. Results No significant difference was observed in the age（F=1.392，P=0.246），body mass index（F=1.969，P=0.120），infertility years（F=0.416，P=0.742），infertility type（χ² =4.693，P=0.196），infertility factors（χ²=7.206，P=0.616），endometrial preparation method（χ² =11.289，P=0.256），basic follicle-stimulating hormone（F=1.736，P=0.161），luteinizing hormone（F=1.894，P=0.132），estradiol（F=1.614，P=0.181），number of previous transplants（χ² =4.041，P=0.257），number of pregnancies（F=0.024，P=0.995），number of miscarriages（F=0.118，P=0.949），number of embryos transferred（F=0.345，P=0.793），and developmental days of the transferred embryos（χ² =1.638，P=0.651） between the control group and the treatment groups. The endometrial thickness and type Ⅲ endometrial blood flow of groups B，C，and D on the day of transplantation were significantly higher than those of group A （7.93±1.34，8.06±0.85，7.79±1.20 vs. 6.81±0.91，F=13.88，P<0.001； 56.7%，54.2%，56.8% vs. 28.8%，χ² =13.70，P=0.003） and so were the embryo implantation rate and clinical pregnancy rate（51.1%，39.2%，48.6% vs. 22.0%，χ² =18.095，P<0.001；65.0%，58.3%，54.5 vs. 28.9%，χ² =16.116，P=0.001）. The biochemical pregnancy rate of groups B and C was significantly higher than that of group A （68.3%，66.7% vs. 40.4%，χ² =10.936，P=0.012）. The multiple pregnancy rate of group D was significantly higher than that of groups B and C（45.8% vs. 20.5%，10.7%，χ² =9.476，P=0.024）. The live birth rate of groups B，C，and D was significantly higher than that of group A（55.0%，47.9%，47.7% vs. 19.2%，χ² =16.410，P=0.001）. There were no significant differences in the early miscarriage rate and preterm birth rate in group A compared with groups B，C，and D（P>0.05），and in the embryo implantation rate，clinical pregnancy rate，biochemical pregnancy rate，early miscarriage rate，and preterm birth rate between groups B，C and D（P>0.05）. Conclusion The monotherapies and combination therapy of endometrial curettage and intrauterine perfusion of G-CSF increase the endometrial thickness and improve the pregnancy outcome after IVF-ET/ICSI in TE patients，with no significant difference in therapeutic effect. Moreover，the combination therapy increases the multiple pregnancy rate and the risk of pathological pregnancy in TE patients with IVF-ET/ICSI compared with the monotherapy.