The invention discloses a phosphorus high-throughput adsorption nano-fiber membrane and a preparation method thereof, and belongs to the technical field of sewage treatment. The preparation method includes the following steps that PVA and PEI are added into deionized water according to the mass ratio of 3 to1, and a PVA/PEI solution is obtained after the PVA and the PEI are completely dissolved at60-90 DEG C; then La(NO3)3.6H2O is added into the PVA/PEI solution to obtain an electrostatic spinning solution, the mass ratio of the total mass of the PVA and the PEI to the mass of La(NO3)3.6H2O in the electrostatic spinning solution is (1 to 10) to (1 to 1), and the total content of the PVA and the PEI in the electrostatic spinning solution is 8 to 12 wt.%; electrostatic spinning is conductedto obtain an electrospinning membrane; and finally, the obtained electrospinning membrane is placed in a 60 DEG C vacuum drying oven, 0.1-5 wt.% of glutaraldehyde is added for fumigation, then the electrospinning membrane is taken out to be put into lye to be soaked, washed by the deionized water to being neutral and then dried, and thus a target product is obtained. The nano-fiber membrane is prepared through an all-water formula, the preparation steps are simple, the prepared phosphorus high-throughput adsorption nano-fiber membrane can efficiently adsorb phosphorus in a water body with thelow concentration, the large water volume and the high flow rate, and the phosphorus removal rate reaches 100%.