The present invention relates to a process for preparing regenerated collagen fiber which comprises treating regenerated collagen fiber with a monofunctional epoxy compound and a metal aluminum salt, in which treatment with the monofunctional epoxy compound initiated by adding sodium hydroxide to become 0.001 to 0.8 N based on the treatment solution and inorganic salt in an amount so that water absorption of the obtained regenerated collagen fiber becomes at most 100%, depending on amount of sodium hydroxide added. Also, the present invention relates to a process for setting regenerated collagen fiber obtained by the above process which comprises thermally setting the fiber by means of wet heat treatment at 50° to 160° C. and drying treatment at 20° to 220° C.