An approach for the selecting continuous tracking navigation area was proposed to solve the problem of navigation area selecting for FLIR visual navigation of air vehicles.The mission of FLIR visual navigation was analyzed,and 4 kinds of commonly used navigation modes were summarized.Then,a navigation area selecting method integrating rough selecting,accurate selecting with stability analysis was designed as for the mission of continuous tracking navigation area selection,based on image variance calculation,continuation straight line feature detection and Frieden gray level entropy.The basic principle,implementation steps and flow chart are given here.The application experiments indicate the practicability,efficiency and adaptability of the designed approach.