The invention discloses a fixed-wing unmanned aerial vehicle PID parameter control method based on an ant colony algorithm. The method comprises steps of setting ant colony search nodes, defining the value range of the PID controller parameters: the scale factor Kp, the integration time Ti and the derivative time Td by the empirical method, and setting the search nodes to an N* 3 search point matrix set of one parameter per line, where N is the number of random values within the range of values greater than 1; adding the pheromone evaporation mechanism to the ant colony optimization mechanism, and evaporating the pheromone on the optimal path of the ant colony search after each turn of iteration; and traversing the ant colony search nodes by using the ant colony optimization mechanism of pheromone evaporation to find the node satisfying the evaluation control performance index, wherein the evaluation control performance index is that the integral of the absolute error is the smallest. The method realizes the optimal PID parameter searching and setting of the fixed-wing unmanned aerial vehicle by using the improved ant colony algorithm, accelerates the searching process of the optimal solution, and is suitable for the multi-condition constrained type combinational optimization.