Oil and gas drilling is an important means and links of oil and gas resources exploration and development. The drilling oil and gas exploration cost in the total costs of oil and gas exploration and development is also large, which influenced the oil and gas exploration and development revenue directly. As the drilling risk factor is rising, it makes drilling cost more and more volatility. So, controlling the risk of oil and gas drilling costs is essential for oil and gas field development cost control. In this paper, based on analysis the components of the oil drilling and the factors influencing the drilling costs risk qualitatively, it analyzes the risk factors influencing the oil drilling cost by using the AHP. It sorts the weight of risk factors, and then it obtains the degree of the influence to the cost of drilling.