In the optical fiber delay directional detection laser warning system, the optical fiber delay lines are used to connect optical incept system with photoelectric conversion system,which plays roles of transmitting the laser,delaying the optical signals and encoding the optical signals simultaneously. Because the length of optical fiber delay lines is different, the laser pulse received by the optical windows will produce different time delay.Thus the transition of the laser azimuth information to the time information is realized.Because the length of optical fiber delay lines has direct effects on the volume of laser warning system, the optical loss ,the false alarm ratio and the optical fiber delay lines are permuted and combined based on the property of the laser pulse and the optimization theory. The optimal design ways of the length of optical fiber delay lines coding are brought forward,and the correlation theory is used for analysis and calculation. Arranging mode of full direction matrix is attained,and accordingly the relevant arranging principle is educed. According to the principal the permutation and combination are put up to the optical fiber delay lines.Accordingly the optimization of the total length of the optical fiber delay lines is obtained in theory, which provides the important theoretical argument for the optimization design of laser directional detection warning system.