The invention discloses a method for preparing a super-hydrophobic micro-porous membrane by synergistic regulation and control phase separation of an inorganic salt aqueous solution. In a membrane casting liquid system consisting of polymers/solvents/additives, the weak non-solvent is beneficial to polymer crystallization, the strong non-solvent is beneficial to rapid gelation and large cavity formation, an inorganic salt crystal grain has the effects of a crystal nucleus and a pore-foaming agent; by utilizing the advantages of the weak non-solvent, the strong non-solvent and the inorganic salt crystal grain, a synergistic effect is realized in the membrane casting liquid separation process, so that the homogeneous super-hydrophobic micro-sphere structure membrane with good pore channel connectivity is prepared. A nano-scale mastoid structure during polymer solidification is formed on the surface of a micro-sphere structure, so that a super-hydrophobic micro-nano structure similar to a lotus leaf surface structure is formed on the surface of the membrane; a membrane body is completely composed of the micro-sphere structure, and a membrane pore has good connectivity and hydrophobicity, therefore, the stability and the durability of the super-hydrophobic micro-porous membrane are improved.