Abstract: At present, batch mixed transportation mode is mainly adopted in the multi-source single-sink liquid light hydrocarbon pipeline network system of China's oil and gas fields. In this mode, different kinds of liquid light hydrocarbon are mixed and transported from multiple hydrocarbon-producing stations to the downstream storage. In the process of transportation, however, the on-site operation planning mainly depends on personnel experience, which may lead to frequent pump startup and shutdown, high operation energy consumption, significant pipeline network hydraulic disturbance and other problems. Based on the discrete time stepping expression method with consideration of various constraints, the mixed-integer nonlinear programming (MINLP) model was built, with the minimum sum of costs, containing transmission pump operation cost and transmission switching operation cost in hydrocarbon production stations, as the objective function. Piecewise linear method was used to deal with the nonlinear constraints, and largescale mathematical programming solver (Gurobi) was used for solution. As a calculation example, one multi-source single-sink liquid light hydrocarbon pipeline network system operating in China was solved, with the solving time of 245.7 s. The solving result improves the stability, safety and economy of the pipeline network operation, and conforms to the field operation process.