To evaluate the effect of two concentrations of intravenous administration of nicardipine hydrochloride on nicardipine-related phlebitis in patients with preeclampsia. A total of 100 preeclampsia patients were administered with nicardipine hydrochloride and divided into the low-concentration (LC) and high-concentration (HC) groups. The incidence and severity of phlebitis, time from treatment to onset of phlebitis, skin temperature, visual analogue scale (VAS) score, induration, and systemic adverse reactions were compared between two groups. The incidence rate of phlebitis in the LC group was 20% (10/50), significantly lower than 42% (21/50) in the HC group (P< 0.05). Ridit Analysis showed that the severity of phlebitis in the LC group was remarkably lower than that in the HC group (P< 0.05). In the LC group, the time from intravenous administration to onset of phlebitis was longer, the average skin temperature was higher, the VAS score was lower, and the indurated area was smaller than those in the HC group (all P< 0.05). Intravenous infusion of nicardipine hydrochloride with constant and low concentration reduces the incidence rate of phlebitis, prolongs the time from treatment to onset of phlebitis, alleviates the severity of phlebitis and pain, maintains skin temperature, and minimizes induration in preeclampsia patients without systemic adverse reactions.