The invention relates to a mechanical section-searching device for citrus sectioning. The mechanical section-searching device includes a citrus ball rotating device fixed to a base, a single-chip microcomputer and a line-searching device. The citrus ball rotating device includes a stepping motor, an upper clamp and a lower clamp. The line-searching device includes a probe seat, a support, a linearmotor and a sliding block. The sliding block is disposed between the linear motor and the stepping motor and driven by the linear motor, the support is fixed to the upper end of the sliding block, one end of the probe seat is fixed to the middle of the support, a piezoelectric sensor and a photoelectric sensor are fixed to the other end of the probe seat, and the photoelectric sensor is located above the piezoelectric sensor. The single-chip microcomputer is located on one side of the linear motor, and the single-chip microcomputer is electrically connected with the piezoelectric sensor, thephotoelectric sensor, the linear motor and the stepping motor. According to the mechanical section-searching device for citrus sectioning, a citrus ball sectioning line can be detected before citrus sectioning, the position of the citrus sectioning line is indicated, working stability of a citrus sectioning device is improved, and the sectioning damage rate is reduced.