The invention relates to the technical field of separating membranes, and in particular to a method of in-situ generation of a nano particle on a separating
membrane surface. The method comprises the following steps: conducting
surface modification on a basic separating
membrane surface for more than once, and conducting in-situ generation of the nano particle for more than once on the separating
membrane surface subjected to the
surface modification, wherein the special points are that the
surface modification refers to the following steps: soaking the basic separating membrane in
dopamine buffer
salt solution with the concentration of 0.001 mg / mL-100 mg / mL and the PH value of 7-12, modifying for 1 min-7 d under the condition that
oxygen or oxidant is participated to form a poly-
dopamine layer on the basic separating membrane surface; the in-situ generation of the nano particle refers to the following steps: soaking the separating membrane with the poly-
dopamine layer generated on the surface in
metal salt solution with the concentration of 0,001-10,000 mM / L for 1 min-300 d to generate the nano particle in situ, or accelerating the in-situ generation of the nano particle under the action of
reducer. Compared with the prior art, the preparation method is simple and easy to be operated, economic, efficient and environmental-friendly, and facilitates industrialisation.