The invention discloses a micromechanical sensor with a conduction assembly and a processing method thereof. The micromechanical sensor comprises an upper cover, a sensitive silicon structure and a lower cover, wherein an upper fixing capacitance plate is arranged on the upper cover, a lower fixing capacitance plate opposite to the upper fixing capacitance plate is arranged on the lower cover, the sensitive silicon structure is arranged between the upper fixing capacitance plate and the lower fixing capacitance plate, the conduction assembly used for guiding a metal electrode of the upper fixing capacitance plate to the lower cover is also arranged between the upper cover and the lower cover, the lead-out problem of electrodes of the upper cover plate is effectively solved, the structure is simple, and the cost is low. The processing method comprises the following steps that S1, the lower cover, the upper cover, the sensitive silicon structure and a conduction silicon bridge are processed; S2, fixed connection is carried out; S3, laser scribing processing is carried out. The processing method has the advantages that simplicity and convenience are realized, the implementation is easy, and the processing cost and the processing process difficulty are greatly reduced.