A hierarchical trimetallic coordination polymer film was prepared using a spray-assisted interface synthetic strategy and in situ deposited onto Ni foam (denoted as Co0.5Ni0.3Fe0.2BDC-HCPF/Ni foam). The as-prepared material exhibits a 3D network hierarchical structure with 1D interconnected nanofibers and can be directly used as an efficient OER electrocatalyst.