Three-proofing finishing method of terylene fabric with high soaping-proof color fastness and high sublimation fastness, finishing agent and preparation method of finishing agent

Aiming at the defects that the soaping-proof color fastness and the sublimation color fastness are not high or are not stable in the prior art after a terylene fabric is finished in a three-proofing way and the three-proofing function and the performance of proofing water washing are not stable as well, the invention provides a three-proofing finishing method of a terylene fabric with high soaping-proof color fastness and high sublimation fastness, a finishing agent and a preparation method of the finishing agent. According to the finishing method, acid-reduction washing is carried out on the basis of traditional reduction washing and three-proofing finishing. The finishing agent comprises three preparations which are an alkali-reduction washing agent, a three-proofing finishing agent and an acid-reduction washing agent. A fabric is finished by adopting the method provided by the invention, acid-reduction washing is carried out after three-proofing finishing, dispersed dye escaping from an amorphous area can be fully washed off so as to act as the aim of fixing the color again, and a terylene fabric with high soaping-proof color fastness and high sublimation color fastness is obtained. Meanwhile, the three-proofing performance and the water-washing proofing performance of the terylene fabric are enhanced, and the initial three-proofing performance is not lowered but is enhanced by about a half grade.