The invention discloses a manufacturing method of a hard-base soft-structure internal combustion engine connecting rod. The method includes the following steps of forging of a blank, coarse grinding of end faces, boring, rough boring of a large-head hole and a small-head hole, chamfering of the large-head hole, threaded hole machining, fracture splitting of a large-head end and assembling, accurate grinding of the end faces, semi-fine boring of the large-head hole and the small-head hole, tegular groove milling and oil groove boring, fine boring of the large-head hole and the small-head hole, flat grinding of the large-head end, parkerizing of the small-head hole, and cover removing, cleaning and assembling. The connecting rod comprises the large-head end, a rod body and a small-head end, the large-head end and the small-head end are arranged at two ends of the rod body respectively, the connecting rod is of an integral structure, and a connecting rod cover is arranged at the large-head end of the connecting rod. The manufacturing method is simple in principle, a manufacturing technique of a traditional internal combustion engine connecting rod is improved to provide a feasible and reliable manufacturing technique for the hard-base soft-structure internal combustion engine connecting rod, and particularly precision and performance of a soft structure of the small-head end of the connecting rod are guaranteed. Meanwhile, the method has the advantages of simple technique and low manufacturing cost, and is convenient for batch production.