This document discloses a method and apparatus for image encoding/decoding which support multiple layers. The method for image decoding comprises analyzing a video parameter set (VPS) extension for layer dependency on a current layer, analyzing slices for layer dependency on a current slice by determining whether not to apply layer dependency to the current slice or to apply new layer dependency to the current slice, the new layer dependency determining within a range of layer dependency analyzed from the VPS extension, and constructing a reference picture list about the current layer based on at least one of layer dependency analyzed from the VPS extension and layer dependency analyzed from the slice.