In recent years, compared with traditional refrigeration technology, the electrocaloric refrigeration technology has been applied in variety of green cooling devices due to its high efficiency and environmentally friendly. Recent findings reveal that the ceramics system with additives (such as, LiBiO2, PbO) can create large ECE under low electric field. In this work, the ternary glass BaO-CaO-SiO2 (BCS) was used as a sintering aid to enhance the electrocaloric (EC) response of 0.2Ba(Ti0.9Sn0.1)O3−0.8Ba(Zr0.18Ti0.82)O3(BZSnT20) bulk ceramics. The EC properties of BZSnT20 could be also improved via controlling sintering temperature and the content of BCS sintering aid. It was found that BZSnT20 with 0.5wt% BCS show the maximum EC response of 3.2K under 7MV/m with sintering temperature of 1262℃. These results demonstrated that the ECE of BZSnT20 can be boosted by using appropriate additives, which provides an effective route to realize large ECE under low electric fields.