The invention discloses a sealing assembly process of a box assembly and a tail door assembly of environmental sanitation equipment, and relates to the technical field of assembly process technology of the environmental sanitation equipment. The technical problems that the operation difficulty of the existing assembling process of the box assembly and the tail door assembly of the environmental sanitation equipment is large, the adjustment allowance is not guaranteed, the later adjustment is not facilitated, and the working efficiency is low are solved. The sealing assembly process comprises the steps of inlaying cushion blocks in a sealing clamping groove, wherein the cushion blocks meeting the size requirement of the assembly thickness are obtained through multiple tests; clamping and fixing the tail door assembly on a tail door frame of the box assembly by adopting a clamp; then, completing the assembly of a driving plate and an oil cylinder locking tail support; sleeving lock hookshafts with bushes, and assembling lock hooks on the box assembly; adjusting the adjusting allowance between the lock hook shafts and the lock hooks through the bushes; and completing assembly of a tail door ear plate assembly. According to the process, the problem that size control over the compression amount and adjusting amount of a sealing rubber strip is unstable can be thoroughly solved.