Objective To study the effect of low-dose dopamine adjuvant therapy on inflammatory factors and prognosis in preterm infants with necrotizing enterocolitis (NEC). Methods A total of 100 preterm infants with NEC from June 2017 to June 2019 were enrolled and divided into a dopamine treatment group and a conventional treatment group using a random number table, with 50 infants in each group. The infants in the conventional treatment group were given symptomatic treatment, and those in the dopamine treatment group were given low-dose dopamine adjuvant therapy in addition to the conventional treatment. ELISA was used to measure the levels of C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), and interleukin-8 (IL-8). The two groups were compared in terms of time to relief of clinical symptoms, fasting time, treatment outcome, prognosis, and adverse reactions. Results Both groups had significant reductions in the levels of CRP, TNF-α, and IL-8 after treatment, and the dopamine treatment group had significantly lower levels of these markers than the conventional treatment group after treatment (P < 0.05). Compared with the conventional treatment group, the dopamine treatment group had significantly shorter time to defecation improvement, time to relief of abdominal distension and diarrhea, and fasting time (P < 0.05), a significantly higher response rate (P < 0.05), and a significantly lower surgery rate (P < 0.05). There were no significant differences in the mortality rate and incidence of adverse events between the two groups (P > 0.05). Conclusions Low-dose dopamine adjuvant therapy can effectively improve the levels of inflammatory factors and clinical symptoms in preterm infants with NEC and has good safety, and therefore, it holds promise for clinical application.