BaTiO3-based ferroelectric materials, which are modified by the substitution of A-site or B-site ions, can potentially be applied in voltage-controlled tunable ceramic capacitors and microwave devices due to their excellent dielectric nonlinearity under DC electric fields. In this paper, the mechanism of dielectric nonlinearity and relative theory of BaTiO3-based ferroelectric materials in ferroelectric phase, paraelectric phase and the phase transformation process are discussed. According to our experimental results and related literatures, the dielectric nonlinearity and applications of BaTiO3-based ferroelectric materials including ceramic blocks and thin and thick films are reviewed. Some technical problems in the research of dielectric non-linear ferroelectric materials are also discussed.