The present invention provides a process for preparing azoxystrobin, which is performed by reacting 2-cyanophenol or a salt thereof with a compound represented by formula I under the catalysis of a trimethylamine catalyst to obtain the azoxystrobin represented by formula II, which allows the yield of the product azoxystrobin to reach 98% or more, the yield of separated product to reach 95% or more and the post-processing to be simple. The trimethylamine catalyst can be recycled and reused in synthesizing the target product azoxystrobin, which not only reduces the cost but also reduces the total nitrogen and COD in wastewater. The advantages regarding of cost and environmental protection of the method according to the present invention are significant and thus the method is suitable for industrial production.