The invention discloses a platform support, an experimental platform and an establishment method thereof. The platform support comprises beams; fixing plates are fixedly connected to the front ends ofthe beams, and front-end supporting leg oil cylinders are further arranged below the fixing plates; front-end supports, support mold frames, back-end supports and press plates are further arranged onthe beams in sequence; a driving oil cylinder is further arranged on each beam; an oil cylinder fixing base is arranged on each beam, the driving oil cylinders are arranged on the oil cylinder fixingbases, and output ends of the driving oil cylinders are connected with the press plates; back-end support leg oil cylinders which are used for driving the oil cylinder fixing bases to ascend or descend are further arranged at the bottoms of the oil cylinder fixing bases. The platform support can be more suitable for being used as a three-dimensional and large-sized similarity simulation test platform support, the mounting workload can be reduced, the operation is simplified, and the aims of accelerating the whole test process and quickly conducting testing can also be achieved.