The invention relates to an ultra-large capacity time division and wavelength division fiber grating sensing system and a query method of the fiber grating sensing system. The ultra-large capacity time division wavelength division fiber grating sensing system consists of a broadband light source, a modulation module, a circulator, a fiber Bragg grating sensing array, a sampling module, a wavelength demodulation instrument and a data processing computer, wherein the modulation module and the sampling module comprise a SOA high-speed photoelectric switch respectively and are driven by different channels of the same signal generator, and a phase difference exists between two drive pulses; and the fiber Bragg grating sensing array can be composed of identical fiber gratings or multi-wavelength fiber gratings. With the adoption of a technology combining a time division multiplexing with a wavelength division multiplexing, tens of thousands of gratings can be engraved on an optical fiber. The ultra-large capacity time division and wavelength division fiber grating sensing system has characteristics of large system capacity, high response speed, good expandability, high flexibility, good stability, low cost and the like, can perform dynamic measurement and static measurement at the same time, and can satisfactorily meet requirements of internet of things on information capacity.