The invention discloses a special material for environment-friendly plastic pipes and a preparation method of the material. The material is prepared from recycled PET (polyethylene terephthalate) and HDPE (high-density polyethylene). The special material for environment-friendly plastic pipes is prepared from components in percentage by mass as follows: 60%-80% of recycled PET, 20%-40% of HDPE and 4%-6% of a compatilizer. Compared with the prior art, the special material has the benefits as follows: the recycled PET is used as a main body, HDPE is used as a modification matrix, the compatilizer is added to improve the interface compatibility of plastic bodies, PET and HDPE which are not compatible originally are mutually fused in a sea-island structure manner, the tensile strength, impact strength, elongation at break, heat-resistant temperature and other properties of the recycled PET material are significantly improved, so that the material has better mechanical properties, is low in cost, can be widely applied to pipe fields such as building water supply and drainage pipes, urban gas pipes, electricity and cable casing pipes, industrial fluid transportation pipes and the like and has significant social and economic benefits.