In order to investigate the phenomenon of gas⁃liquid bias in parallel separators in oil⁃gas gathering and transportation system, an experiment facility for gas⁃liquid two⁃phase splitting was designed, constructed and instrumented. Flow rates, pressure, pressure drop，liquid level and liquid holdup were measured and recorded by data⁃acquisition system. Gas⁃liquid splitting pipelines of two geometries (horizontal pipeline⁃T junction⁃ horizontal pipeline and horizontal pipeline⁃T junction⁃vertical pipeline) were constructed. Experiments on splitting of slug flow were carried out and splitting characteristics of gas⁃liquid were studied with symmetrical and asymmetrical pipeline conditions. When the pipeline conditions are symmetrical, the two phases of slug flow splitting into two separators are even for pipelines of two geometries. When the pipeline conditions at the outlets of separators are asymmetrical, mal⁃distribution of both two phases occurs and liquid tends to split more evenly than gas. Based on the calculation of pressure drop, a splitting model was established and the influence of gas⁃liquid velocity on the flow characteristics was explained simply.