Objective To study the splenic injuries caused by high-altitude falling and underwater explosion and the 2-dimensional ultrasound and contrast-enhanced ultrasound (CEUS) characteristics. Methods Twenty-three healthy Beagle dogs were divided into high-altitude falling group (n=13) and underwater explosion group (n=10).Free-fall high-platform device and gram-grade trinitrotoluene were used to simulate high-altitude falling injury and underwater explosion injury in Beagle dogs, respectively.Ultrasound examination of the spleen was performed immediately after injury, with follow-up examinations every hour.CEUS examination was performed in surviving dogs.Spleen specimens were taken from deceased dogs after injury to observe gross injuries.Pathological changes in tissue morphology and cell apoptosis were observed by hematoxylin-eosin (H-E) staining. Results In the high-altitude falling model, 6, 2, 1, and 1 dogs died in the 6 m, 7 m, 8 m, and 9 m groups, respectively; in the underwater explosion model, 1 and 4 dogs died in the buoyancy and frogman groups, respectively.Two-dimensional ultrasound examination of the high-altitude falling model showed spleen rupture (disruption of splenic parenchymal structure), perisplenic fluid accumulation, subcapsular hematoma, intrasplenic hematoma, increased splenic vein echo, and uneven splenic parenchymal echo.Two-dimensional ultrasound examination of the underwater explosion model showed increased splenic vein echo and uneven splenic parenchymal echo, which were less serious compared with the high-altitude falling model.CEUS results indicated 4 major contrast patterns in both models.The Beagle dogs with type Ⅰ (large focal contrast defect), type Ⅱ (diffuse contrast defect), or type Ⅲ (no contrast agent entry into the splenic vein) contrast patterns all had splenic rupture after injury.H-E staining results showed true splenic rupture, diffuse intrasplenic hemorrhage, splenic hematoma/ecchymosis, subcapsular hematoma/ecchymosis, and venous congestion after spleen injury, which were consistent with the 2-dimensional ultrasound findings. Conclusion High-altitude falling causes more serious spleen injuries in Beagle dogs compared with underwater explosions.Routine ultrasound performs well in diagnosing typical splenic injuries, while CEUS has advantages in evaluating atypical splenic injuries and has good predictive ability for delayed splenic rupture.