A warming fixation device for premature infants was made and its clinical application effect was discussed. The warming fixation device for premature infants was designed and used in clinic. Sixty premature infants admitted to the neonatal ward of Baoding Hospital, Beijing Children's Hospital, Capital Medical University from January to June 2022 were selected as the control group, and 60 premature infants admitted from July to December 2022 were selected as the experimental group. In the control group, umbilical vein catheterization or central vein catheterization were performed using Astro Boy heating box, restraint band or artificial restraint. The preterm infants in the experimental group were radiated into the Astro Boy warm box with self-designed preterm warming fixation device for catheterization. The time of catheterization, the number of limb protrusion, the number of participants in catheterization operation, and the body temperature from 20 minutes of catheterization operation to the end of catheterization operation were recorded in the two groups. The frequency of hypothermia (< 36.5 centigrade) was calculated, and the differences in various indexes between the two groups were compared. (1) The warming fixation device for premature babies consists of two parts: warm sleeping bag and soft pad. The warm sleeping bag includes 4 parts: head, arm, chest and abdomen, and lower limbs. The chest and abdomen were designed with rectangular covering cloth, which can be opened to facilitate umbilical vein puncture for premature infants. There were 3 groups of restraint belts on the rectangular soft pad, which can respectively fix the arms, chest and abdomen of the warm sleeping bag and the lower limbs. During the catheterization operation, use Velcro to secure the warm sleeping bag to the cushioned surface, and select the area of exposed skin according to the piercing site. (2) There were no significant differences in gender, body weight and gestational age between the experimental group and the control group [male: 48.3% vs. 46.7%, body weight (kg): 1.86±0.06 vs. 1.82±0.06, gestational age (weeks): 31.33±0.31 vs. 32.25±0.34, all P > 0.05]. Compared with the control group, the catheterization time of experimental group was significantly shortened (minutes: 21.30±0.43 vs. 30.02±0.64, P < 0.01), the number of limb protrusion was significantly reduced (0 time: 70.0% vs. 33.3%, 1 time: 26.7% vs. 50.0%, P < 0.01), and the number of participants in catheterization operation was significantly reduced (people: 1.77±0.06 vs. 2.37±0.06, P < 0.01). The frequency of hypothermia in experimental group was significantly lower than that in the control group [6.12% (6/98) vs. 26.50% (31/117), χ2 = 15.536, P < 0.01]. The warming fixation device for premature infants is convenient to use, which can effectively shorten the tube placement time, save human resources, and reduce the incidence of hypothermia in premature infants.