Recently, high entropy ceramics developed by researchers inspired by high entropy alloy have attracted wide attention, due to which can provide new design ideas for the development of non-metallic materials with excellent properties. In this work, based on perovskite ceramic BaMO3, a series of Li-doped high-entropy ceramics Ba(Ti1/7Sn1/7Zr1/7Hf1/7Nb1/7Ga1/7Li(1/7-x))O3 (x = 0, 2.3%, 5.3%, 8.3%, 11.3%) were successfully prepared by solid state reaction. The effects of Li content on the high entropy ceramic phase structure, microstructure and dielectric properties were investigated. The results show that the grain sizes of these ceramics are uniform, and the effect of Li content on the structure of ceramics is not significant. All ceramics are of cubic perovskite structure without obvious impurity phase. When x = 0, the ceramic is represented as seven-component equimolar high entropy ceramic Ba(Ti1/7Sn1/7Zr1/7Hf1/7Nb1/7Ga1/7Li1/7)O3, which exhibits excellent dielectric properties, with dielectric constant reached the maximum value of 2920 (@ 100 Hz), nearly 50 times as much as the value of Li-undoped six-component equimolar high entropy ceramic Ba (Ti1/6Sn1/6 Zr1/6 Hf1/6 Nb1/6 Ga1/6) O3.