In this study we analyzed factors affecting the life cycle of technology, quantified the evaluation criteria that will affect the life of the individual technologies, and finally proposed the improvements to calculate technology life cycle that the properties of individual technologies are reflected based on cited-patent life time(CLT). It is expected that the methodology proposed improves the limits of the existing standard model, presents more reasonable criteria and ease of persuasion on the results derived by appraisers, and finally gives a lot of the feasibility and the usability of technology life cycle derived by the improved method to appraisers.