The invention discloses the formula, the production process and the application of moisture absorbent and sweat conductive comfortable finishing agent which is used for modifying the polyester fiber to enable the polyester fiber to have moisture absorbent and sweat conductive capabilities. The formula of the moisture absorbent and sweat conductive comfortable finishing agent contains: polyethylene glycol, ethylene glycol, polyether and dimethyl terephthalate. The two-step continuous production process is adopted: in the first step of esterifying, polyethylene glycol, ethylene glycol, polyether and dimethyl terephthalate are put into a reaction vessel for esterification under the action of catalysts; and in the second step that the material produced after the esterification is transported to a polymerization kettle for polymerization under the actions of high temperature, vacuum, and catalysts, in order to generate polyester-polyether copolymer with high molecular weight to be 30000-50000, namely, the moisture absorbent and sweat conductive comfortable finishing agent. The moisture absorbent and sweat conductive comfortable finishing agent can be directly used or be used after being mixed with substances such as amino silicone oil and so on, and carry out chemical modification on the polyester fiber.