The invention provides a multi-UUV (
Unmanned Underwater Vehicle) cooperative 
system underwater target tracking 
algorithm for a 
fuzzy adaptive interacting multiple model (FAIMM). Firstly, according to the bearing-only target tracking principle of the multi-UUV cooperative 
system, a discrete nonlinear state and observation equation for the target 
tracking system is built; then, according to the characteristics of 
underwater target motion, in combination of five kinds of target motion 
modes, analysis is carried out according to the dynamic 
state transition matrix, the coupled inequality relation among the five 
modes is put forward, and a 
motion mode set adapted to 
underwater target tracking is selected optimally; then, an intermediate Gauss 
distribution function is adopted as a 
membership function, a mode probability is used as an evaluation index for filter information and corresponding 
covariance acquired by each mode, and 
fuzzy reasoning for the mode transition probability is designed; and finally, the FAIMM 
algorithm is designed and realized. During the multi-UUV cooperative 
system bearing-only target tracking process, the least number of target motion sets is selected, 
adaptive change of the mode transition probability is realized through the 
fuzzy reasoning, disordered competition among the 
modes are reduced, the filter accuracy is higher, and demands of multi-UUV cooperative system underwater target tracking can be met.