A method and apparatus for improved deblocking filter are disclosed. In one embodiment according to the present invention, determining the non-zero transform coefficients existence for a PU-only boundary is skipped and therefore the deblocking filter for PU-only boundary is eliminated if the condition of boundary strength equal to 1 is not fulfilled to avoid unnecessary deblocking. In another embodiment of the present invention, three gradients are determined for two pixel lines and filter ON/OFF decision is made based on the three gradient values of the two pixel lines. One aspect of the invention is related to filter strength selection between strong and weak filters. According to one embodiment, the filter strength selection is based on various gradient values of a pixel line across the block boundary. Another aspect of the invention is related to the weak filter.