Ferroelectric materials with a morphotropic phase boundary (MPB) can exhibit enhanced dielectric, piezoelectric, and electrooptic properties, compared with conventional ferroelectric materials. In this paper, dense (1-x)Ba2NaNb5O15-x Sr2KNb5O15 (BNN-SKN) tungsten bronze structured ceramics of binary solid solution system were obtained by a solid-state sintering method. The microstructure and electric properties of BNN-SKN were investigated to explore the potential MPB regions. The MPB coexisting with Ccm2 and P4bm appears as x=0.7. As the SKN content increases, the phase transition temperature and dielectric constant of the measured samples reach their extreme values as x=0.7, i.e., Tm =170, eTR =1 211, and em=3 326. In addition, the ferroelectric properties of BNN-SKN system were also analyzed, and the factors affecting the ferroelectric change in this binary system were discussed.