The present invention relates to a steel rail temporary fixing structure and a longitudinal blocking groove block installation and construction method. The steel rail temporary fixing structure comprises a plate body, a steel rail assembly, the temporary fasteners and the noise reduction blocks, the steel rail assembly comprises a steel rail, and the top face of the plate body is provided with a rail bearing groove formed in an inwards-concave manner. The steel rail is arranged in the rail bearing grooveand is fixed to the plate body through the temporary fasteners, the noise reduction blocksare installed between every two longitudinally-adjacent temporary fasteners and at the inner side and the outer side of the steel rail, the bottoms of the noise reduction blocks are embedded between the steel rail assembly and the groove wall of the rail bearing groove, and the tops of the noise reduction blocks extend to the positions below a rail head. The steel rail temporary fixing structure and the longitudinal blocking groove block installation and construction method are suitable for temporarily fixing the steel rail during the construction process of a continuous supporting rail system, after a rail line is stabilized, the temporary fasteners are disassembled, then the longitudinal blocking groove blocks are installed, and a polymer damping material is poured to fix the steel railassembly permanently, so that the steel rail can be supported and locked continuously, the vibration source generated by the steel rail under the external forces can be eliminated basically, the wheelrail contact relation can be improved, the abrasion of a wheel rail is greatly reduced, and the service life of the wheel rail is prolonged.