Abstract: In order to offer the high resolution ²⁴¹Am alpha source used in the real-time monitoring of nuclear power plant safety operation, the magnetohydrodynamic electrodeposition method was built, and the equipment and processes were designed. The ²⁴¹Am sources were prepared by this method, and the deposition conditions were optimized. The optimal deposition conditions are as follows: (NH₄)₂SO₄ concentration is 0.5 mol/L as deposition solution, the current density is 180 mA/cm², the distance between platinum anode and stainless steel cathode is 5 mm, the magnetic induction at the center of the source slice is 0.193 T, pH of deposition solution is 2.0-2.5, and the deposition time is 1 h. The results show that ²⁴¹Am can be deposited quantitatively on the cathode, the deposition yield is nearly to 100%, and the energy resolution is 15.0% higher than that without the magnetic field. The uniformity and firnmess of ²⁴¹Am sources were inspected, and the results show that the uniformity and firnmess of the sources prepared by the magnetohydrodynamic electrodeposition method are both good.