In response to the need for IPv6 protocol access to the spatial communication network, the implementation of the Neighbor Discovery Protocol(NDP) on the FPGA-based IPv6 over CCSDS-AOS gateway is discussed. It is proposed to build the NDP protocol module on the IPv6 over CCSDS-AOS gateway system to realize the gateway address resolution. The function of NDP protocol module is realized through state machine control. Experiments show that the design solves the problems of IPv6 over CCSDS-AOS gateway's active and passive address resolution, neighbor cache table lookup and management without requiring the gateway to perform protocol conversion and forwarding on the NDP protocol. It has been applied in IPv6 over CCSDS-AOS gateways.