The invention discloses a large-scale complex structure health monitoring system based on multiagent cooperation. The system comprises a data monitoring layer, a data interpretation layer, a damage diagnosis layer, an information fusion layer and an input and output layer. The data monitoring layer, the data interpretation layer, the damage diagnosis layer, the information fusion layer and the input and output layer are successively connected. The data monitoring layer sends collected structure health state information to the data interpretation layer. The data interpretation layer extracts astructure damage characteristic parameter from the structure health state information and sends the acquired structure damage characteristic parameter to the damage diagnosis layer. The damage diagnosis layer sends an assessment result to the information fusion layer. The information fusion layer carries out fusion and decision making on a structure damage assessment result, acquires an integral damage state of a structure and sends the integral damage state of the structure to the input and output layer. In the system, through multiagent cooperation, a complexity of a needed decision object is greatly reduced, and an amount of information which needs to be processed, transmitted and decided is decreased.