The invention relates to a navy detection model construction method. The navy detection model construction method comprises the steps of (1) conducting 
task segmentation on a set of sample data to obtain a plurality tasks, and extracting average features to obtain a training sample set of the tasks; (2) selecting the features of the tasks to obtain a feature weight matrix of the tasks; (3) setting a threshold value 
delta, judging whether the maximum value of one 
column vector in the feature weight matrix is larger than the threshold value 
delta or not, and if yes, executing the step (4); if not, abandoning the 
column vector, and executing the step (5); (4) adding the 
column vector into a sharing feature item set; (5) judging whether columns vectors which are not compared with the threshold value 
delta exit in the feature weight matrix or not, and if yes, executing the step (3); if not, executing the step (6); (6) inputting a new training 
data set; (7) obtaining a linear classification value through calculation; (8) setting a navy threshold value, and determining that data are from a navy when the linear classification value is larger than the navy threshold value. According to the navy detection model construction method, a navy detection model is built through a multi-
task learning method, so that a navy user is conveniently and rapidly recognized.