Based on the electromagnetic forming process of 5A02 aluminum alloy reducer pipe, the influences of coil turns and discharge voltage on the forming accuracy of reducer pipe were studied by numerical simulation and forming experiments combined with fracture morphology analysis, and the reasons for the performance changes of 5A02 aluminum alloy after electromagnetic forming were explored. The results show that with the increasing of coil turns, the range of magnetic field action increases. When the number of coil turns n is 20, the pipe fittings could achieve good mold adhesion. As the voltage gradually increases, the combined effect of work hardening and pulse electromagnetic field leads to increase first and then decrease in the elongation of material. The tensile strength and hardness almost unchange after increasing. When the discharge voltage is 8 kV, the maximum die gap of pipe fittings is 0.12 mm, which is less than 0.2 mm meeting the forming requirements. Simultaneously, with the increasing of voltage, the number of ductile dimples on the tensile fracture surface of pipe fittings gradually decreases. However, when the voltage reaches 8 kV, the number of ductile dimples increases to some extent.