In product life cycle assessment (LCA), investigation of supply chain is so difficult and time-consuming that it is often overlooked, which significantly compromises LCA quality and credibility. Specialized tools for supply chain investigation are expected to solve this problem. An online LCA system, namely eFootprint, was introduced in this paper; this system was developed to conduct full LCA study online, including supply chain investigation, life cycle modeling, and analysis. Based on eFootprint's features, the guidelines for conducting LCA online were proposed. A pilot study of a refrigerator showed that eFootprint is a promising solution for more efficient and higher quality LCA work.