This paper focuses on the investigation of magnetic properties of Ni nanowire arrays synthesized using Al2O3 porous templates with different durations of first anodization. It has been shown that the diameter of the pores in the template is increasing with an increase in the first anodization time up to 2 hours, and the interpore distance becomes more uniform. Using porous templates with short times of anodization results in synthesis of branched Ni nanowires, while templates with longer times allow to achieve cylindrical nanostructures. Magnetic properties of Ni nanowires arrays were studied using the FORC method, which allowed to investigate the distribution of interaction fields and coercive forces in the arrays. It was found that two magnetic phases with different coercive forces and interaction field are observed in the samples with a short duration of first anodization.