The present invention relates to a deblocking filtering method, a method for inducing bs (boundary strength) therefor, and a method and an apparatus for encoding/decoding using the same. The method for inducing the bS of the present invention comprises the steps of: inducing a boundary of a deblocking filtering unit block as a unit block for applying the deblocking filtering; and setting the bS according to each bS setting unit block within the deblocking filtering unit block, wherein the bS setting step can set a bS value for a target boundary corresponding to a boundary of the deblocking filtering unit block as the bs setting unit block.