System identification is a technique used to generate mathematical models of dynamic systems based on observation data. This chapter explains how to use system identification methods to obtain guidance models and aerodynamic parameters of micro-small fixed-wing Unmanned Aerial Vehicles (UAVs) through four progressive experiments: a basic experiment, an analysis experiment, a design experiment, and a Hardware-In-the-Loop (HIL) experiment. The objective is to deepen the understanding of fixed-wing UAV identification. This chapter describes the introduction of the MATLAB System Identification Toolbox in the basic experiment for identifying guidance models using flight log data. The analysis experiment involves identifying aerodynamic derivatives and examining the impact of various input signals on the identification results. The design experiment involves conducting experiments to identify the parameters of three attitude moment channels. Finally, the guidance model and aerodynamic parameters will be identified based on HIL simulation data. For more information on this chapter, please refer to the link.