The invention discloses a high-precision remote optical path switch scheme and a system, belonging to the technical filed of optical networking communication. An on-line monitoring and switching unit exchanges information with a remote console by Ethernet or a GPRS mode, a main optical-fibre circuit and an auxiliary optical-fibre circuit are utilized to transmit optical signals, and optical signal power is monitored and compared with a set switching threshold to determine whether the optical path switching is gated; the system comprises the on-line monitoring and switching unit, a communication control unit and the like; the on-line monitoring and switching unit is composed of an optical splitter, a photodiode, a logarithm amplifier, an A/D converter, an optical switch and a control chip; and by introducing the logarithm amplifier, the accuracy of the optical power acquisition value of the traditional fibre is effectively improved, and the problem that the precision is difficult to be accurately measured due to larger attenuate generated after long distance transmission of an optical fibre trunk network is improved, thereby ensuring more accurate and reliable optical path switch in traditional optical path protection. In addition, after the communication control unit is introduced, remote centralized management on an optical path protection module is realized.