A white-light interferometric fiber optical sensing network based on the double-ring topology is demonstrated, which can be applied to the measurements of quasi-distributed strain and temperature in a smart structure. In order to increase the multiplexing capacity, decrease the measurement cost of each single point sensor, and improve the ability to resist destruction of the sensor network by resorting to the double-port inquiring technology, the double-ring fiber optical sensing network based on the space division multiplexing (SDM) is further developed. The low-coherent multiplexing principle in the double-ring network structure is analyzed. And based on the optical path matching condition of space division multiplexing, the intensity characteristic of the interference signal in the sensor is deduced. The characteristics of double-ring sensing network connecting 9 sensors and its property of resisting destruction are verified by experiments, and the results of experiments are analyzed and discussed.