OBJECTIVE：To investigate the efficacy of hormone combined with cyclophosphamide in the treatment of connective tissue disease-associated interstitial lung disease （CTD-ILD）and to analyze its influential factors. METHODS ：100 patients diagnosed as CTD-ILD in our hospital from Jan. 2018 to Jan. 2019 were randomly divided into observation group and control group ，with 50 cases in each group. Control group was treated with Compound cyclophosphamide tablets ，50 mg each time，3-4 times each day. Observation group was additionally treated with Prednisone acetate tablets ，10 mg each time ，3-4 times each day ，on the basis of control group. Treatment courses of 2 groups lasted for 6 months. The clinical efficacy ，the occurrence of ADR，lung function before and after treatment ，the levels of peripheral IL- 6，CRP and PCT and quality of life （SGRQ score ）were compared between 2 groups. According to the therapeutic efficacy ，all patients were divided into effective group and ineffective group. The related factors influencing the clinical efficacy of CTD-ILD were analyzed by univariate and multivariate Logistic regression analysis. RESULTS ：After treatment ，total response rate ，FVC，FEV1 and DLCO of observation group were significantly higher than those of control group ，while SGRQ score ，levels of IL- 6，CRP and PCT in peripheral blood were significantly lower than control group （P＜0.05）. There was no significant difference in the total incidence of ADR between 2 groups（P＞0.05）. Univariate analysis showed that there were no significant differences in gender ，age，past medical history and CTD type between effective group and ineffective group （P＞0.05）. However ，there were statistical significancant differences in the distribution of different levels of IL- 6，CRP and PCT in peripheral blood between 2 groups（P＜0.05）. Multivariate Logistic regression analysis showed that IL- 6 was an independent risk factor for therapeutic efficacy of combined therapy [OR （95％CI）＝ 4.537（3.668，10.352），P＝0.002]. CONCLUSIONS ：Hormone combined with cyclophosphamide can significantly improve the therapeutic efficacy of CTD-ILD patients ，improve their lung function and quality of life ，and reduce the expression level of inflammatory factors. The level of IL- 6 is an independent risk factor affecting the efficacy of the treatment ，and its changes should be paid close attention to during the treatment.