Provided are a water engineering seepage behavior fusing and sensing system and method. The system comprises a seepage-hidden optical fiber locating device, a seepage flow velocity distributed optical fiber monitoring device, an online seepage line diagnosis device and a seepage behavior optical fiber self-adaptive identification device, the location of a water engineering seepage point is realized by using the seepage-hidden optical fiber locating device, then, the seepage flow velocity of a water engineering is monitored by virtue of the seepage flow velocity distributed optical fiber monitoring device, the online diagnosis of a seepage line on a section of a whole water engineering structure can be realized by using the online seepage line diagnosis device, and finally, the current seepage behavior is integrally monitored and evaluated by using the seepage behavior optical fiber self-adaptive identification device, so that the water engineering seepage behavior fusing and sensing is completed. The optical information change of the optical fiber is acquired from multiple aspects and angles by using the four water engineering seepage monitoring devices, depending on the material and mechanical properties of the water engineering and relying on a distributed optical fiber monitoring technology, and furthermore, the monitoring and sensing of a seepage behavior of a water engineering are indirectly completed.