A ferrofluid droplet on a plate undergoes interesting fission under a magnetic field. In this article, a recently developed simplified multiphase lattice Boltzmann method coupled with a self-correction solution for the magnetic potential equation is employed to explore this complex flow phenomenon. It is found that the droplet fission follows a fourpattern process under a nonuniform magnetic field. The mechanisms behind this behavior are influenced by the strength and gradient of the magnetic field, surface tension, droplet size, and the wetting boundary condition. These findings provide valuable insights into the application of ferrofluids in droplet microfluidics and contribute to advancements in this field.