The embodiments of the invention provide a rail dynamic rigidity detection apparatus and a rail dynamic rigidity detection system, and relate to the technical field of rail detection. The rail dynamic rigidity detection apparatus comprises a vibration exciter, a fixing device connected with the vibration exciter, a force sensor connected with the vibration exciter, a displacement sensor connected with a steel rail, a data acquisition device connected with the force sensor and the displacement sensor, a computer connected with the data acquisition device, and a clamp component used for clamping and fixing the steel rail and connected with the force sensor. The clamp component comprises a clamp connector, a clamp base, a first clamping plate, and a second clamping plate. The clamp connector is connected between the clamp base and the force sensor. The side of the clamp base away from the clamp connector matches the surface of the steel rail. The technical scheme provided by the invention has the advantages of convenient and quick installation and disassembly, stable and reliable force transmission, and high detection accuracy.