The invention relates to a method for determining laser beam rider guidance information field initial fixed focus parameters. The method comprises the following steps of: (1) determining an entire missile guidance control system chart; (2) determining a mathematical model of each pane of the control system chart; (3) stringing the mathematical model of a lead compensation network to the control system chart; (4) designing a lead compensation network according to the requirements of the system on convergence rate of an introduction section trajectory; and (5) designing laser link transfer coefficients so that a step response curve of the laser link transfer coefficients is closest to the step response curve of the lead compensation network. The design results of the laser link transfer coefficients obtained from the step (5) are the laser beam rider guidance information field initial fixed focus parameters determined by the invention. The method provided by the invention can be used for fast and accurately designing the laser beam rider guidance information field initial fixed focus parameters and meets the requirements of the system on convergence rate of an introduction section trajectory.