To investigate the effect of the intrauterine infusion of growth hormone for treating patients with the resistant thin endometrium, and to study the pregnancy outcomes of the freeze-thaw embryo transfer (FET) of the patients. Methods: A total of 93 patients with the resistant thin endometrium refractory thin endometrium who wanted FET in the hospital were selected and were randomly divided into two groups from January 2015 to August 2022. 41 patients in the study group were given the intrauterine infusion of growth hormone combined with the hormone replacement therapy, and 52 patients in the control group were given the hormone replacement therapy. All the patients in the two groups were prepared their endometrium with an alternative cycle before FET. The therapy effect and the pregnancy outcomes of the patients in the two groups were observed. Results: The endometrial thickness (7.69±0.71 mm) on the day of FET transformation of the patients in the study group was significantly higher than that (6.63±0.49 mm) of the patients in the control group (P<0.05). The difference value of the endometrial thickness (1.98±0.91 mm) of the patients in the study group between the day of FET transformation and the day of HCG injection in fresh cycle was significantly higher than that (0.79±0.66 mm) of the patients in the control group (P<0.05). The proportions of the type A (80.5%) and type B (14.6%) endometrial  morphology, and the type I  (73.2%) and type II (19.5%) endometrial blood flow of the patients in the study group had significantly different from those (51.9% and 40.4%, and 48.1% and 42.3%) of the patients in the control group (P<0.05). The rates of the clinical pregnancy rate and the live birth of the patients in the study group after FET were 41.5% and 29.3%, and which were significantly different from those (21.2% and 11.5%) of the patients in the control group (P<0.05). The biochemical pregnancy rate (26.8%) and the abortion rate (29.4%) of the patients in the study group after FET had no significant different from those (19.2% and 45.5%) of the patients in the control group (P>0.05). When the endometrial thickness of the patients on the day of FET transformation was less than 7mm, there was no significant difference in the pregnancy outcomes of the patients between the two groups. There were no significant differences in the incidences of preterm birth, placental adhesion and postpartum hemorrhage of the patients with live birth between the two groups. Conclusion: The intrauterine infusion of growth hormone for treating patients with the resistant thin endometrium has significantly therapeutic effect on promoting their endometrial growth, which can increase the pregnancy rate and improve the pregnancy outcomes of the patients.