The invention relates to a demoulding method for a concrete precast member. The demoulding method comprises the specific steps that (1) an isolation coating is arranged on the inner surface of a mould plate, specifically, the isolation coating is arranged in a mode of spraying or painting isolating agents; (2) a lining cloth impregnated with demoulding liquid is fixed on the outer side of the isolation coating on the mould plate; and (3) at the time of construction, formwork erecting, concrete pouring and demoulding operation can be conducted according to a conventional construction method. The method that a layer of the isolating agents is firstly smeared on the inner surface of the mould plate and a layer of the lining cloth which is impregnated with the demoulding liquid is further fixed is adopted, demoulding is easy, the situation that the lining cloth is not adhered to the concrete surface can be guaranteed, and the effects that the surface of the mould plate is protected against being scratched and corrosion are achieved.