It is still a great challenge to prepare novel CuO-based crystal materials with low-dimensional magnetic structures. A new copper oxyborate, namely, PbCu6B6O16 was synthesized and structurally characterized for the first time. Its structure features a novel 3D framework which can be considered as building from the layers of [Cu6B6O16](infinity)(2-) interconnected by corner or edge sharing of CuO4, BO3, B2O5, and B3O7 groups, where Pb2+ cations are located in the free space within the layer. It is unexpected that the compound contains fundamental building block (FBB) formed by three different borate anionic groups, including BO3 triangle, and condensed branched BO3 triangles (B2O5 and B3O7). In particular, according to our survey, the branched B3O7 group is unprecedented. Our work provides useful information on the design and search for novel low dimensional copper borates, and also helps to strengthen the understanding of the investigation of borate structures.