Nitrogen doped porous carbon was used to immobilize acetylcholinesterase(AChE) to fabricate biosensor for the detection of organophosphorus pesticide phorate.The peak current was 0.195 8 μA at the AChE/GC electrode,while 0.841 4 μA was obtained at AChE/nitrogen doped porous carbon/GC electrode,indicating that nitrogen doped porous carbon can effectively immobilize AChE and enhance the sensitivity.The inhibition rate versus logarithm of phorate were linear in the range of 6.0×10-10-1.2×10-6 g/L,with a correlation coefficient(r2) of 0.998 5.The detection limit of phorate,calculated by inhibition rate of 10%,was 5.8×10-12 g/L.The sensor could be used for the detection of phorate in spinach juice with recoveries of 91.7%-97.4%.