The invention discloses a rotary assembling and box body conveying and pushing system for instruments. According to the system, front shells are involved; a front shell conveying unit and a front shell screening unit are further arranged; the front shell conveying unit comprises a front shell vibration assembly and a front shell conveying mechanism; the front shell screening unit is connected to the front shell conveying mechanism and comprises a chassis; a first front shell rotating disc is arranged on the upper surface of the chassis; second front shell rotating discs are further arranged in the first front shell rotating disc; and detection assemblies are arranged above the second front shell rotating discs and detect the current states of the front shells so as to screen the front shells. The system has the beneficial effects that 1, the front shell conveying unit is arranged so that the front shells meeting the requirements can be conveyed from irregular front shells, conveying of the front shells can be accelerated, and therefore the production efficiency can be improved; and 2, the front shell screening unit is arranged so that the state of the front shell conveying unit in an assembling system can be screened so that the front shells meeting requirements can enter an assembling subsystem of a next element.