In　the　trace　fusion　system,　it　is　the　unitary　way　and　high　cost　to　get　the　data　sources　of　air-defense　radar.　Aiming　at　those　shortcomings,　this　paper　gives　a　method　to　generate　data　based　on　the　model　of　target＇s　trail　and　the　detection　simulation　of　air　radar.　The　emphasis　is　placed　on　the　model　of　target＇s　trail　and　the　process　of　air-defense　radar　detection.　Fist　of　all,　the　trail　model　is　built　up　on　the　flight　plane,　and　then　converted　into　rectangular　coordinates　system.　The　radar　detection　model　simulates　the　detection　process　to　estimate　whether　the　target　can　be　found.　The　real-time　trace　data　is　obtained　if　the　target　is　found.　The　experiments　validated　the　models　and　algorithms.　©　2010　IEEE.