In software product line (SPL) development, evolutions occur in core assets and application products. How to ensure their alignment in evolution is a big challenge. Products in an SPL share a reference architecture, which centers in SPL development and evolution, so architectural evolution management is a natural and essential choice for SPL. In this paper, we propose an architecture-based evolution management method for SPL, in which both architecture and component evolutions are supported. An integrated version model for both core assets and application products is proposed. Based on the model, the method provides evolution processes for architectures and components, both supporting forward customizations and backward feedbacks by merging and synchronization. The prototype tool for the method has been developed on the open-source version control system Subversion, and preliminary application has shown that it can effectively support SPL evolutions.