The invention, which belongs to the technical field of inertial instruments, relates to a floater running-in device of a three-floating inertial instrument. The floater running-in device comprises a athree-floating inertial instrument floater (a to-be-tested test piece), a multi-channel motor power supply, a multi-channel electric signal monitoring module, a multi-channel temperature collecting module, a program-controlled temperature box and a host computer. And a plurality of three-floating inertial instrument floaters can be driven simultaneously to carry out running-in screening. According to the floater running-in device, the manual operation is replaced by the automatic control operation so as to realize timing automatic starting and stopping of running in and automatic collection and recording of data of the running-in process, so that the operator is freed from the monotonous and boring data recording work. Besides, the real-time monitoring and automatic processing functions for the running-in abnormity are introduced into the floater running-in device, so that the reliability of the running-in equipment is improved. When the running-in abnormity occurs, response to the abnormity is made timely and automatic grading processing is performed; and the float or equipment is protected from being damaged by the running-in abnormity.