The mix proportion and construction technology of the concrete filled steel tube of the Longtan River Bridge were introduced. The construction process showed that the concrete has many advantages such as good workability, high strength (both early and long time) and proper expansive properties. The hammer beating detecting, ultrasonic detecting and boring core detecting showed that the concrete in the tubes and binding planks was very dense. There was not cracks existing between the concrete and steel tube or between the binding planks, which means that the combination structure formed from the concrete and steel tube is rational.