Valves and limiting rings are commonly used in current pipeline system, and the nature of the pipeline equipped with limiting devices is a typical continuous mutation pipeline. There is an obvious local head loss in the flow of the abrupt change pipeline, so the engineers have to consider the local head loss caused by the abrupt change of the pipeline in the pipeline system design. At present, the local head loss of single mutation pipe flow has been widely researched, and the corresponding calculating model has been set up. However, less study was conducted for continuous mutation pipe head loss. In engineering design, the superposition calculation method based on the head loss of single mutation pipeline is adopted for the local head loss calculation of continuous mutation pipe. The error of the local head loss of the continuous mutation pipeline is large based on this superposition calculation method of head loss of a single abrupt change pipeline because the flow of the continuous mutation pipeline is very complex. In view of this, this article adopts the method of combining theoretical derivation and experiment designs four kinds of pipes with different diameter ratio and 23 kinds of inlet flow conditions, carries on the experiment with aviation kerosene as the medium, analyzes the experimental results, and modifies the traditional superposition method of calculating the local head loss. A modified calculation model for local head loss of continuous sudden contraction and expansion pipeline is proposed. Compared with the traditional calculation method and experiment data, the accuracy of of the calculation result is significantly advanced, which provides an effective method for the calculation of local head loss of continuous sudden expansion pipeline in the design of complex engineering pipeline system.