The invention discloses an on-line surrounding rock strength identification method of hard rock heading equipment. The strength of surrounding rock of the heading face is identified through an existing surrounding rock cutting model according to sensing information of the heading equipment. According to the method, the problems that the method for detecting the rock strength through surrounding rock sampling is high in cost and poor in real-time performance are solved, and the strength of the surrounding rock can be identified in real time according to the sensing information of the heading machine; the problem that in the actual construction process, constructors highly depend on individual experience to judge the strength condition of the surrounding rock is effectively processed, dependency of the constructors on experience can be reduced, and then it is guaranteed that construction is safer, more reliable and more efficient; signals are processed by adopting an interative least square method, the calculation amount is decreased, the identification precision is improved, and real-time identification on the strength of the surrounding rock of the heading face of the heading equipment is promoted.