A ring backup structure with consistent amplitude and phase employs a structure framework consisting of n product devices and 2 working backup product devices. The key portion of the structure is that: a time delay and dispersion compensation network is added in the ring backup interconnection to ensure that the amplitude and phase features of the product devices are not changed when backup switching is performed. The backup product devices are arranged at the two ends in the structure, the working product devices are arranged in order, if one of the product device has faults, product devicesat the upper end and the lower end are subjected to upward switching and downward switching in order so as to ensure that the relative amplitude and phase features between the product devices are notchanged; if two adjacent product devices have faults, a switching mode is performed (ditto); if two non-adjacent product devices have faults, intermediate product devices are not switched, product devices at two sides are switched, and therefore, the relative amplitude and phase features of the product devices are changed least.