The invention relates to a preparation process and application of a dinitrogen oxide heterocyclic compound. The preparation process is characterized in that a N,N-diacyl dinitrogen oxide heterocycliccompound is used as the raw material, the N,N-diacyl dinitrogen oxide heterocyclic compound is allowed to have reaction with alkali in a nonpolar solvent to obtain the dinitrogen oxide heterocyclic compound, and the dinitrogen oxide heterocyclic compound is subjected to further reaction to be converted into herbicides such as pinoxaden. Compared with the prior art, the preparation process is highin yield, convenient to operate, little in waste gas, wastewater and solid waste and beneficial to industrial production.