The crystalline solid-air in the liquid hydrogen will cause erosion or friction on the elbow, which is directly related to the safety of liquid hydrogen transportation. The CFD-DPM model was used to study the erosion characteristics of solid-air to liquid hydrogen pipelines. Results show that the outer wall of the cryogenic liquid hydrogen elbow has serious erosion in the range of 60-90 degrees, which is different from the general elbow. The erosion rate is linearly positively correlated with the mass flow of solid-air particles, and the erosion rate has a power function relationship with the liquid hydrogen flow rate. The fitted relationship curve can be used to predict the characteristics and range of the elbow erosion. The structure of the liquid hydrogen elbow also has an important influence on the solid-cavity erosion characteristics. The increase of the radius of curvature is conducive to the reduction of the maximum erosion rate, while the average erosion rate undergoes a process of increasing and then decreasing. The radius of curvature is 60 mm, which is the inflection point of the average erosion rate of the 90 degrees elbow. The research results are expected to provide a theoretical basis for the prevention of liquid hydrogen pipeline erosion.