The reliability evaluation for the bridge in service can provide a scientific basis for decision-making in bridge repair and reinforcement. A comprehensive method for reliability evaluation was introduced in this paper based on a long span continuous bridge with variable section evaluation. Appearance survey of the bridge, concrete strength and carbonization test, static test and dynamic test would be done as well as the finite element simulation model to determine the properties of the bridge for reliability evaluation. The relationship of the natural frequency stiffness evaluation method and the effective coefficient method would be established in this paper based on the test results. Based on the static and dynamic test, we classify the bridge as class 3 while the bending stiffness is good, the dynamic rigidity is a little weak, and the damping coefficient a little larger.