An enclosure for air compressors is generally composed of a first shell body and a second shell body, wherein the first shell body defines a plurality of through holes, and the second shell body is formed with a plurality of snap joints. Each through hole is defined by a cylindrical surface and a substantially conical surface, between which a step is defined. In use, the snap joints can be inserted into the through holes respectively to have the snap joints snatched by the steps 14 formed in the through holes, so that the first and second shell bodies can be quickly assembled. In addition, a disassembly tool can be inserted into each through hole to have the snap joints removed from the through holes, so that the enclosure can be quickly disassembled.