The invention provides a preparation technology of regenerated polyester high-modulus and low-shrinkage fibers. The preparation technology comprises the following steps: S1, crushing recycled PET (Polyethylene Terephthalate) to obtain a PET crushed material; drying the PET crushed material in drying equipment; S2, conveying the dried PET crushed material into a decomposition tank and immersing; S3, putting the immersed recycled PET and clean water for immersing into a reaction kettle together and keeping for 10 to 20min; S4, pouring the recycled PET in the reaction kettle out and spinning anddrying; then conveying the PET into a drying device and carrying out drying treatment; then conveying the PET into a circular disc rotor type reactor to obtain a PET melt; then adding a tackifying andnucleating agent; S5, granulating the tackified and polymerized recycled PET melt to obtain regenerated PET grains; adding an antistatic agent which accounts for 0.2 to 1 percent of the weight of theregenerated PET grains into the regenerated PET grains and mixing in a stirring machine to obtain a mixture; S6, pressurizing and extruding the mixture and filtering; spraying out from a spinning nozzle; enabling spinning fine flow to pass through an air layer with the size of 10 to 50mm and enter an acetone condensation bath, and condensing and forming; then carrying out stretching and sizing through three pairs of hot rollers to prepare the high-modulus and low-shrinkage fibers.