The invention relates to a process for comprehensively utilizing flax seed skin. The process comprises the following steps of: taking the flax seed skin as a raw material, degreasing the flax seed skin by solvent-extracted oil No.6, filtering, and drying flax seed skin powder; recovering the solvent-extracted oil No.6 from a filtrate to obtain flax oil; immersing the flax seed skin powder to water for degumming and then carrying out solid-liquid separation to obtain glue liquor and a solid matter such as flax dietary fiber powder; adding the glue liquor to ethanol, stirring for precipitation separation, drying and smashing the solid matter to obtain flax glue; carrying out alkaline hydrolysis on supernate, adding hydrochloric acid for neutralization, concentrating the mixture to dryness, adding the ethanol for filtering, and recovering ethanol solution to obtain a flax lignan crude product; adding the ethanol to the solid matter of the flax dietary fiber powder for standing, carrying out solid-liquid separation, air-drying the solid matter such as flax dietary fiber, and recycling the ethanol from the solution; and superfinely grinding the air-dried flax dietary fiber to obtain the superfine flax dietary fiber powder. By utilizing the process, four products can be obtained by one process, the flax seed skin is comprehensively developed and utilized furthest, and the additional value of the flax seed skin is enhanced.