A series of tests based on large scale model are designed to study dynamic response of pile-broad subgrade, aiming at structure’s response towards different load frequency and structure’s performance under long-term dynamic load. The test results indicate that dynamic stress of reinforcement and soil decrease slightly with load frequency, while accelerations trend to increase. Soil under loading plate has certain supporting effect because stress of reinforcement is smaller in test group with soil remains. Performance of pile-board subgrade under long-term dynamic load is steady and reliable since none of stress and displacement varies obviously when loading times increase to 106. Ultimate bearing capacity of pile-board subgrade is much bigger than actual demand, so the structural type of pile-broad plate remains to be optimized.