【Abstract】 Objective To investigate the changes and correlation analysis of serum inflammatory factors and thyroid hormones in children with neonatal respiratory distress syndrome (NRDS) and infectious pneumonia. Methods Children with NRDS (NRDS group), infective pneumonia group (infective pneumonia group) and normal newborns (control group) were selected with 35 cases in each group. The inflammatory factor interleukin6 (IL6), tumor necrosis factorα (TNFα) and thyroid hormone were measured in all three groups. At the same time, the disease children were given symptomatic treatment, compared with the different stages of detection results and correlation analysis. Results Before treatmen，the ratios of T3, T4, FT3, FT4, γT3, IL6 and TNFα in the NRDS group were significantly different from those in the control group (P＜005). Within the group, T3, T4, FT3 and FT4 were significantly increased and IL6 was significantly decreased after treatment (P＜005). After treatment,γT3 in NRDS group was significantly lower than that in control group(P＜005), but there was no significant difference in other indexes (P＞005). The level of T3 in infective pneumonia group was significantly lower than that in control group (P＜005)，TSH, IL6 and TNFα were significantly increased (P＜005). TSH, IL6 and TNFα were significantly increased (P＜005). After treatment, T3 was significantly higher than before treatment. TSH, IL6 and TNFα were significantly decreased (P＜005), and there was no significant difference between the indexes of the children after treatment and the control group (P＞005). Correlation analysis showed that serum IL6 was negatively correlated with T3, T4, FT3, FT4 and other thyroid hormones in the neonatal respiratory distress group (r was0794,0572,0369,0517, P was 0000, 0000，0029, 0001, respectively). Serum IL6, TNFα and T3 were negatively correlated in the children with infectious pneumonia (r was0887,0783, P was 0000, 0000, respectively). Conclusion Serum IL6 was negatively correlated with thyroid hormones such as T3, T4, FT3 and FT4 in the neonatal respiratory distress group. Serum IL6, TNFα and T3 were negatively correlated in the children with infectious pneumonia. It has a certain clinical reference value in the severity of the disease.