Bio-based polyhydric alcohol prepared by using rape seed oil

The invention discloses a rape oil preparing biological radical polyatomic alcohol method, which comprises the following steps: naking the rape oil and epoxidation agent to carry on epoxidation reaction; generating epoxy rape oil; proceeding epoxy key open cycle reaction with generated epoxy rape oil and nucleophilic reagent with reactive hydrogen; getting mixed hydroxy fatty acid glycerin fat; adding in amine or alcohol amine; heating-up to proceeding alcoholysis reaction; getting mixed hydroxy fatty acid monoesters-biological radical polyatomic alcohol. The invention has degree of functionality and high reaction active. The raw material is cheap and easy to get.