The invention provides a dynamic test detecting platform for a metal structure of a crane, comprising a vibrating system, an excitation system, a data collecting and analyzing system and a track. By using the dynamic test detecting platform for the metal structure of the crane, various loads of the crane in a working or non-working state, like a seismic load, body shaking of a floating crane, cart emergency brake, a collision load of a cart buffer, road spectra, a hoisting load, a cargo deflection load, sudden rising of cargo, falling of a lifting appliance or cargo unloading, a periodic fatigue load and a combination of the loads, can be simulated; dynamic response signals of a crane test piece, such as data of a stress, strain, a displacement, an acceleration and the like, can be collected, processed and displayed to detect the state of the crane test piece; and the dynamic test detecting platform is suitable for dynamic experiment detection of the whole crane or the metal structural part.