Objective To investigate whether the sternum angle can be used as an anatomical marker indicating the depth of insertion of right internal jugular venous catheters in infants. Methods A total of 80 children with congenital heart disease, aged 1 to 12 months, who underwent right internal jugular venous puncture and catheterization under general anesthesia from June 2020 to June 2021 were enrolled. The patients were subjected to right internal jugular venous puncture and catheterization under general anesthesia. The distance from the skin puncture point (I) to the supraclavicular notch (A), and the vertical distance from the supraclavicular notch to the level of sternal angle (B) were measured, and the IA+AB distance was recorded as the depth (D) of insertion of central venous catheter (CVC). The chest X-ray examination was taken routinely after the operation. The relative positions of the catheter tip and carina on the image were observed, and the vertical distance between them (F) was measured and the distance from the puncture point to the carina (E) was calculated, and the related complications were recorded. Multiple linear stepwise regression analysis was performed to determine the factors that predicted the depth of deep vein catheterization. Results A total of 79 children underwent right internal jugular venous puncture and catheterization, of which 24 patients (30.4%) had central venous catheter tips above the level of the carina, 8 patients (10.1%) had central venous catheter tips above the level of the carina, and 47 patients (59.5%) had central venous catheter tips below the level of the carina. None of the children had serious complications. D was 5.0 (4.5, 5.5) cm, F was 2.0 (1.0, 4.0) mm, and E was 4.9 (4.4, 5.3) cm. Multiple linear regression analysis showed that D was correlated with height and age (P<0.05). The multiple linear equations are as follows: CVC insertion depth (cm) =1.899+0.180× age (m) +0.036× height (cm). Conclusions The sternal angle is a safe and reliable anatomical marker for measuring the depth of insertion of right internal jugular venous catheterization in infants, which can easily and quickly complete central venous catheterization.