This study presents the development of a four-phase, four-fluid flow pipeline simulator to describe simultaneous flow of gas, oil, water, and hydrate through a pipeline. The model has been equipped with a phase behavior model and hydrate equilibrium model to efficiently estimate thermodynamic and hydrodynamic properties of multicomponent mixtures. The governing equations are formulated for describing the physical phenomena of mass, momentum, and heat transfers between the fluids, and the wall. The equations are solved by utilizing the implicit finite-difference method on the staggered-grid system which can properly describe the boundary conditions as well as phase appearance or disappearance. The developed pipeline simulator has been validated against the field data presented by a previous investigator, and their matches are found to be relatively excellent. The model also has been applied to a multi-component, four-phase flow system in order to examine the transient flow characteristics in pipeline. Also, the potential and the location of hydrate formed in the pipeline have been studied by analyzing the flow characteristics. As a result, it was found that a pipeline system flowing gas, oil, water, and hydrate could be optimized by systematically investigating the hydrodynamic variables for the prevention of hydrate formation.