The invention belongs to the fields of environmental microbiology and agriculture, and relates to an amidase gene dimtH for degrading dimethoate, chlorpropham and propanil amide, and an encoded protein and application thereof. The amidase gene dimtH for degrading the dimethoate, the chlorpropham and the propanil amide has the full length of 1,395bp, and the sequence shown as SEQ ID NO.1; and a product encoded by the gene, namely amidase DimtH comprises 465 amino acids and has the sequence shown as SEQ ID NO.2. The DimtH can degrade a pesticide of dimethoate and herbicides of chlorpropham and propanil amide. The amidase gene dimtH can be used for constructing transgenic crops capable of degrading the pesticide of dimethoate and the herbicides of chlorpropham and propanil amide, also can beused for the removal of residues of the pesticide of dimethoate and the herbicides of chlorpropham and propanil amide from soil and water and the bioconversion in medicine synthesis, and has important theoretical and application value.