The proliferation of hydrogen fuel cell vehicles calls for effective planning of hydrogen supply facilities. This paper focuses on renewable energy-based distributed hydrogen supply networks (DHSNs), with on-site production and vehicle-based transport. To explore the energy synergism effect, we propose multinetwork constrained planning of hydrogen-power supplying facilities. Considering the double-layer coupling mechanism (DCM), multiple DHSN equipment planning is coordinated with the generation planning of the power distributed networks (PDN). Firstly, the DCM is proposed considering structured multi-component equipment, inter-layer hydrogen couplings, and cross-network power couplings. Secondly, to formulate the DCM, we develop a structured deployment model for DHSN equipment to enhance system integrality and non-redundancy. Specially, to release more flexibilities, inter-layer transport is modeled by proposing a spatiotemporal extended vehicle routing problem model incorporating multiple loading stations with trip coordination. Thirdly, a planning method is proposed to coordinate the planning of hydrogen-power supply facilities in coupled networks, incorporating the double-layer coupling constraints, station operation constraints, and PDN constraints. Test systems are employed to verify the effectiveness of the proposed method.