The CP violation in $K$ and B decays are discussed with the emphasize on the precise prediction for $��'/��$ and the new physics effects from a class of models with additional Higgs doublets and fermions. The contributions from standard model with two-Higgs-doublet (S2HDM) to $K$, $B$ mixing and decays are briefly reviewed. The possible large effects on CP violation in $B\to ��K$ is discussed in an extended standard model with both an additional Higgs doublet and fourth generation quarks (S2HDM4). We show that although the S2HDM and the Standard model with fourth generation quarks alone are not likely to largely change the effective $\sin 2��$ from the decay of $B \to ��K_S $, the S2HDM4 model can easily account for the possible large deviation of $\sin 2 ��$ without conflicting with other experimental constraints.

Talk given at ICHEP04, August 16, 2004,Beijing. 4 pages. Typos corrected