The real electro magnetic（EM） environment effects on unmanned aerial vehicle（UAV） is analyzed.And the max harmful outside word EM environment level to UAV is gained after many electromagnetic compatibility（EMC） tests in darkroom and in actual flying field

which is 60-200 V/m in 0.1-8×103MHz bandwidth.The EMC standard at the system level of UAV is advanced as 10-60V/m in 0.1-2×103MHz bandwidth after analyzing the combined effects of conducted and radiated interferences based on the common EM radiated and conducted characteristics of UAV.The UAV was tested in real flying ground by 410A susceptivity testing system and by simulated electromagnetic pulse（EMP） test according to military testing method GJB3567-99.The results reveal that all air-borne equipments based on this standard can work normally and do not degrade

which indicates the standard can provide an effective evacuating rule for EMC of UAV.