Office is a necessary workplace for corporate business operation in current commercial market, the maturity of office market development reflects the economy and commercial development status in different markets. The application of transacted office rental and vacancy rate as a primary data is relatively rare in pervious domestic literatures due to the difficultly of primary data collection. Therefore, the study of the correlation between office rental and vacancy rate by using primary data analysis is one of the research focus. Moreover, the lack of land supply for office development in Taipei CBD led to a rapid growth for suburban technology parks in the past decade. Corporate occupiers may relocate from the CBD to suburban technology parks due to competitive rental, improved public transportation network and information technology infrastructure. Therefore, the study of the correlation between suburban technology parks¡¦ office new supply and CBD Grade A office vacancy rate is another research focus in this thesis. The scope of study covers the Taipei CBD office submarkets and Neihu Technology Park and Nankang Software Park within suburban of Taipei City. The research method includes a literature review, market overview of CBD and suburban technology parks and empirical analysis of research data. By using correlation coefficient and ordinary least squares methods to analyze the factors, there are two finding revealed in the empirical results. Firstly, the empirical results revealed that the relationship between Taipei CBD Grade A office rental and vacancy rate is negative. Rental drop while vacancy increasing and oppositely rental increase while vacancy rate decline. The grade A rental may drop NT$27.16 per ping per month when Grade A vacancy rate increase 1%. Secondly, the empirical results revealed that the relationship between suburban technology parks¡¦ office new supply and CBD Grade A office vacancy rate is positive. The Grade A office vacancy rate may increase 1.53% when suburban technology parks increase 10,000 pings office new supply. NT$27.16 per ping per month when grade A vacancy rate increase 1%. It would be helpful for making business decisions on office leasing, real estate development and property investment if corporate occupiers, real estate developer and investor have more knowledge on office market vacancy rate and new supply information.