The invention relates to the technical field of new materials, and particularly relates to high-performance environment-friendly modified PBT (polybutylene terephthalate) which is prepared from a component A and a component B, wherein the component A is a PBT raw material, and the PBT raw material is an original new material or is prepared by mixing a reclaimed material with a new material; and the component B is an auxiliary material, and the auxiliary material at least comprises halogen-free flame retardant, toughener, compatilizer and a glass fiber. In the preparation process, the high-performance environment-friendly modified PBT comprises the following specific components in percentage by weight: 15-20% of halogen-free flame retardant, 5-10% of toughener, 3-5% of compatilizer, 25-35% of glass fiber and the balance of PBT raw material; and the preparation process comprises the following steps: performing molecular decomposition, recombining, and granulating. According to the invention, the high-performance environment-friendly modified PBT is prepared by using PBT as a carrier and adding the halogen-free flame retardant, the toughener, the compatilizer, the glass fiber and other auxiliary materials; the invention can enhance the fire retardance degree and physical properties of the product, and ensures that the product meets the environmental requirements for no halogen and no phosphorus and conforms to industrial utilization; and the product is free of I and Br, thereby doing no harm to environment and health of people.