Heavy-duty gas turbine is used widely in power generation industry for many advantages. Gas turbine inlet system is an important component of the gas turbine. The work to study the inlet elbow system was less in the past. In fact, structure design of the inlet elbow system has important influence on performance and life of the gas turbine. In this paper, the three-dimensional structural model of gas turbine inlet elbow system is built; the stress field for the inlet elbow system is analyzed by using finite element method (FEM). The maximum stress and distribution characteristics of stress field in the inlet elbow system is computed. It provides a reliable basis for reasonable design and safety evaluation of the inlet elbow system in gas turbine.