The invention aims to provide a dynamic detection method of horizontal bearing capacity of a long piled wharf structure. The dynamic detection method includes the steps of: 1) determining a to-be-detected zone of the long piled wharf structure and the corresponding type of an impact ship; 2) according to the determined to-be-detected zone, installing a first detection device on the long piled wharf structure for measuring change parameters; 3) enabling the impact ship to impact the long piled wharf structure; 4) according to data obtained during the impact, obtaining static load on and displacement of the long piled wharf structure in the horizontal direction by means of the first detection device; 5) drawing a plurality of bearing capacity curves according to the static load and the displacement, and evaluating the horizontal bearing capacity of the long piled wharf structure by means of the bearing capacity curves. Compared with the prior art, the method allows a worker to evaluate the bearing capacity of the long piled wharf structure conveniently in the horizontal direction through the bearing capacity curves, thereby completing effective detection of the bearing capacity of the long piled wharf structure in the horizontal direction.