In　order　to　study　the　influence　of　aerodynamic　performance　of　micro　quadrotor　aircraft　with　different　rotor　spacing　in　hover,　both　the　thrust　and　power　of　the　micro　quadrotor　aircraft　are　analyzed　with　the　experimental　and　numerical　simulation　results.For　the　experiments,　thrust　and　power　of　quadrotor　with　rotor　spacing　ratios　arranged　from　1.1　to　2.0　are　measured　to　find　out　the　optimal　rotor　arrangement　the　best　aerodynamic　performance.Additionally,　CFD　is　applied　to　obtain　the　accurate　effect　of　aerodynamic　interference　between　rotors　with　the　pressure　distribution,　streamline　distribution　and　vorticity　distribution.Combined　with　the　experimental　results,　different　aerodynamic　characteristics　with　different　rotor　ratio　are　analyzed　theoretically.Results　showed　that　moderate　aerodynamic　interference　between　quadrotor　can　keep　the　vortexes　intact,　so　that　the　thrust　can　be　increased　effectively　compared　with　the　isolated　single　rotor.At　last,　the　rotor　spacing　at　1.8d　is　proved　to　be　the　optimal　rotor　arrangement　with　biggest　power　loading　and　best　aerodynamic　characteristics.　©　2020,　Editorial　Office　of　Chinese　Journal　of　Computational　Mechanics.　All　right　reserved.