The purpose of this study is to conduct a case study for procurement of CO₂ emissions reduction concrete in the construction site. For this purpose, mix-proportion and energy consumption for ready mixed concrete were collected from 27 ready mixed concrete manufacturing plant in Korea using on-line questionnaire, visiting, telephone conversation and so on. And Concrete CO₂ emission assessment was conducted observing Life Cycle Assessment method defined by ISO 14040 series with mix-proportion and energy consumption. With this, CO₂ emission characteristic was analyzed dividing into the group such as compressive strength, admixture, plant region using the result of assessment. Furthermore, comparison analysis of real CO₂ emission of a concrete plant and the minimum CO₂ emission following was conducted.