The invention discloses a large-capacity fiber grating sensing and monitoring system, which belongs to field of fiber sensing, comprising a broadband light source, a tunable filter, a signal processing system, a photodetector, 1 x 2 couplers, 1 x 8 optical switches, 8 optical splitters, 32 fiber delay lines, and 32 fiber Bragg grating sensors which are connected in serial. The sensing network is arranged through connecting fiber grading sensors of different centre wavelengths in serial and connecting a plurality of sensors in parallel, through the time delay of the fiber delay line, the reflected signals of different paths are separated in time sequence, therefore, the signal processing system can distinguish the source of the signal according to the differences of the receiving time combining with the number information stored in the memory, realizes the combination of the time division multiplex and the wavelength division multiplex, the number of measuring points is four times that of the only-used the wavelength division multiplex, is dependent on the length difference of the time-delay fiber, the impulse width and the duty ratio, therefore, the number of measuring points is more, the measuring range is large, and multi-point distributed large-capacity monitoring can be conducted.