The invention relates to a synchronous control system for a pushing pawl device, a center box device and an automatic machine in an encapsulating machine. The output end of a main control unit is connected with a main motor control loop; a main motor drives the automatic machine to rotate through a transmission device; a synchronous control unit acquires rotating speed data of the main motor through an encoder and respectively controls a pushing pawl motor and a center box motor through two servo drivers; the main control unit and the synchronous control unit are communicated with each other. A method comprises the following steps: a cam table is generated by the synchronous control unit according to set parameters; the synchronous control unit reads data of the encoder; if the automatic machine driven by the main motor is in place, the cam table is started, and the data of the encoder are zeroed; the pushing pawl device and the center box device operate synchronously; at the end of synchronous operation, the synchronous control system returns to the step of reading the data of the encoder. According to the synchronous control system disclosed by the invention, the faults of asynchronism and easiness in collision of an original production line are improved, mechanical damage caused by collision is reduced, normal operation of production is guaranteed, and the maintenance cost is reduced.