Abstract: The laser warning is the important precondition and basic measure in laser countermeasure. The first technical problem for the laser warning is how to recognize a targeting laser signal from complex background noise and accurately raise the alarm. The relationship between detection probability of laser warning equipment and signaltonoise ratio is analyzed. It can be seen form the relational expression that, the increase of the signaltonoise ratio of laser signal is a precondition for improving the detection probability. In order to ensure the optimization of the system signaltonoise ratio, an adaptive method was proposed to ensure maximum signaltonoise ratio. The algorithm analysis was carried out and the algorithm simplification was made with the matrix transformation. Finally, a simple iterative algorithm suitable for the optimum weight vector solution is given.