The invention discloses an iron-rich high-entropy alloy powder material for 3D printing and a preparation method thereof. The molar ratio of the iron-rich high-entropy alloy powder material FexAlCoCrNiB0.3 is as follows: the molar weight of Fe is 2 to 3, the molar weights of Al, Co, Cr and Ni are 1, the molar ratio of B is 0.3, and B is added in an Ni-B alloy form. The iron-rich high-entropy alloy powder material is prepared through a medium frequency induction melting gas atomization one-step method, namely, a metal liquid subjected to medium frequency induction melting and refining is directly fed into a gas atomization device through a guide tube and a tundish to be atomized for powder material preparation. According to the iron-rich high-entropy alloy powder FexAlCoCrNiB0.3material prepared through the method, a phase structure is composed of solid solutions of simple face-centered cubic and body-centered cubic structures, and a product is good in degree of sphericity, controllable in particle size, uniform in components, low in oxygen content and good in fluidity; and according to the preparation method provided by the invention, the technology is simple, the energy consumption is low, the control is easy, the product quality is stable, and the method is applicable to large-scale industrial production, pollution-free to the environment, and environment-friendly in utilization.