The invention discloses a miniature fixed wing unmanned aerial plane guidance computer and a guidance method and belongs to the technical field of unmanned aerial plane control. The guidance computer is composed of a power panel and a control signal processing board. The power panel comprises a power transformation circuit module and a simulation reference voltage module. The control signal processing panel comprises an IO driving module, a simulation signal conditioning module, a digital signal conditioning module and a CPU module. The guidance method of the invention can be compatible with the two tracking modes of vertex tracking and fixed distance tracking. The vertex tracking and fixed distance tracking guidance method adopts a unified form, and two types of tracking guidance modes are realized by only sending a variable value instruction. The invention can automatically switch the tracking mode of the unmanned aerial vehicle according to the change of the ground movement speed, can artificially control the tracking mode according to the remote control instruction, and can improve the tracking efficiency and ensure the security when the unmanned aerial vehicle is switching the tracking mode.