The goal of the defense acquisition program is finding the most effective system with the least cost. There are two key functions to achieve this goal: measuring the effectiveness and estimating the cost of each alternative. However, the acquisition procedure of a new weapon system is very complex and uncertain, because it involves anticipating the advantages and disadvantages both friendly and adversaries currently and/or in the future. Also estimating the Life Cycle Cost requires time and huge amount of data. The U.S. Department of Defense Instruction 5000 series was prepared to show how to avoid these complexities and uncertainties, known as a Cost and Operational Effectiveness Analysis (COEA). The main purpose of this study is to show the COEA procedures and format by following the procedures specified in U.S. DoD Instruction 5000 series with an example of the future artillery system in Korea. As background, the concepts and terminologies of COEA and field artillery fire support are briefly examined. Following the format and procedures, the focus of this study is on the measures of the operational effectiveness of the field artillery system by using the computer simulation. The result of the simulation with different scenarios quantifies the performance characteristics and shows the relative effectiveness of each alternative. The other parts are also explained briefly. The acquisition issues partly covers the inferiority of military balance between South and North Korea, and estimating costs for each alternative analyzed with a short example because of the lack of data and time limit. This thesis concludes with a summary of the results so that it discriminates and ranks each alternative.