A large electrocaloric effect (ECE) near room temperature is reported in Sn doped BaTiO3 ceramics. By tuning Ba(Ti1−xSnx)O3 compositions which also exhibit relaxor ferroelectric response to near the invariant critical point, the Ba(Ti1−xSnx)O3 bulk ceramics at x ∼ 0.12 exhibit a large EC coefficient (ΔT/ΔE =0.27*10−6K⋅mV−1) over a 50 K temperature range. In addition to that, the diffuse phase transition is successfully applied to broaden the EC peaks under low electric field. These properties added together indicate a general solution of the electrocaloric materials with high performance for practical cooling applications.