The invention discloses a sequential controller for a multi-mode mobile terminal and its application method, which includes a voltage control crystal oscillator that provides basis-frequency to the phase-locked loop, and a public latch signal that is provided by a physical layer entity controlled by software to each single-mode sequential controller. The sequential controlling method is that an order for latch is sent to the single-mode sequential controllers of the multi-mode terminals to achieve a precise synchronization in all the single-mode systems of the terminals in order to accomplish the cross-switching service. |