The invention provides copper-based brazing paste, a copper-based pre-alloy and a preparation method of the copper-based brazing paste and the copper-based pre-alloy. Wherein the copper-based brazing paste comprises the following components: 65-75 parts by mass of a copper-based pre-alloy; 10 parts by mass to 20 parts by mass of brazing flux; 5 to 18 parts by mass of an organic binder; 1 to 10 parts by mass of an inorganic binder; wherein the inorganic binder is sodium silicate. In the technical scheme provided by the invention, the inorganic binder is added to replace part of the organic binder, so that the organic binder is more stable in the brazing process and is not easy to catch fire.