The invention relates to a preparation method of a three-dimensional zinc oxide/nickel oxide sensitive material and solves the problems that the gas sensitive material for detection of ammonia gas islow in sensitivity, slow in response speed and poor in selection stability. The three-dimensional zinc oxide/nickel oxide sensitive material is prepared by taking zinc acetate, nickel acetate, glycineand ammonium hydrogen carbonate as raw materials and performing hydro-thermal synthesis through a reaction kettle, vacuum aerobic calcination, high temperature heat treatment and grinding and sievingon the raw materials. The preparation method is advanced in process, the data are accurate and detailed; the product is good in appearance and is in a flower-like hierarchical structure; the single flower size is smaller than or equal to 5 microns; the sheet thickness is smaller than or equal to 30 nm; the product has good purity of up to 99.5%; the preparation method can be used in the gas sensor for detection of ammonia gas and is an advanced preparation method of the three-dimensional zinc oxide/nickel oxide sensitive material.