Ultrafine BaTiO3 presents attractive dielectric properties. In this paper, BaTiO3/epoxy composite samples were prepared with different ultrafine BaTiO3 content of 1%, 10%, 20%, 30%, 40%, 50%, 60%, 75.8%, respectively. The dielectric and ferroelectric properties were investigated only from the view of powder characteristics. The results showed that two dielectric peaks in the temperature dependence curves of dielectric constant, and the second peak moved towards the higher temperature with frequency increasing. By comparing different conversion theories, Logarithm theory was thought to be the most reasonable for the situation we discussed. It is indicated that the interaction zone between BaTiO3 particles and epoxy resin is formed and the surface effect plays an important role in dielectric relaxation phenomenon of ultrafine BaTiO3 particles. In addition, the organic-inorganic composite might be a significant method to estimate the properties of ultrafine particles.