Due to the combined impact of global population aging, increased life expectancy, fertility decline, and changing family structures, a growing segment of the population facing retirement is in danger of poverty and economic insecurity. As a result of their advanced age many elderly have lost their ability to earn an income, causing some to be penniless the rest of their lives. Therefore, the purpose of a government or a private run pension system is to provide a mechanism using financial tools to protect the entire structure for old age economic security. This paper not only introduces the philosophy and basic concept of a general pension system, but also examines a United States model, providing a closer look at a major developed industrial country’s national social security program, and corporate pension system. It also describes the experience of reforms on the development process of the United States retirement pension system. This paper studies the various corporate pension schemes in the United States and their possible application as models to countries such as Taiwan. In focusing on the United States corporate pension system in private sector, legal and economic issues are scrutinized. Theories which related to the pension system are first analyzed; then the definitions of the various retirement plans are given. The history of private pension schemes of the United States is told, starting with the American Express, then crude railroad retirement plans to the post-war demand to current United States retirement plans. Analysis of the changes in private sector's pension plan participation for defined benefits and defined contribution plans are examined in light of the impact these changes have made upon retirement income resources. Focus on the IBM Corporation is made as an example of a private sector business in the United States, and this study tracks the evolution of the company’s pension schemes from defined benefit pension plans to the newer hybrid cash balance pension plans and the now-popular defined contribution 401(k) pension plans. Findings show that the United States corporate pension system is not feasible as a model at this time because of its many deficiencies in its laws and regulations, and also because of the currently shaky global economy. Suggestions and possible remedies are given on how to strengthen the corporate retirement pension system in United States.