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In this paper, a two-stage beamforming scheme called domain selective neighbor-based joint spatial division and multiplexing (DS-NJSDM) scheme is proposed to reduce the overhead of pilot training and uplink feedback in Frequency Division Duplexing (FDD) three-dimensional (3D) massive multi-input multi-output (MIMO) systems. Inspired by the Kronecker product structure of the 3D channel model, a DS pre-beamformer is proposed to sparsify the channel matrix, which selects horizontal or vertical pre-beamformer to mitigate the interference from non-neighbors. The signal space can be effectively utilized with the DS pre-beamformer, and the complexity of beamforming is significantly reduced. After the pre-beamformer, the zero entries of the downlink channel matrix are randomly distributed, making pilot design difficult. Then, a pilot allocation scheme is proposed to design the pilot matrix. Simulation results are …