This　paper　presents　experiments　carried　out　to　study　the　effects　of　nonlinear　oscillation　on　horizontal　gas-liquid　two-phase　flow.　The　experiments　considered　the　nonlinear　oscillation　over　a　wide　range　of　vibration　parameters.　Flow　regime,　transition　boundary,　frictional　pressure　drop　and　void　fraction　were　measured　using　a　high-speed　camera,　pressure　sensor　and　electrical　impedance.　Six　typical　flow　regimes　were　observed.　The　frictional　pressure　drop　and　void　fraction　in　steady　state　and　nonlinear　oscillation　were　compared.　It　found　that　the　traditional　predictive　correlations　for　frictional　pressure　drop　were　accurate　and　matched　the　measured　frictional　pressure　drop　closely.　On　the　other　hand,　the　prediction　performance　of　selected　void　fraction　correlations　based　on　three　typical　models　was　below　par　for　the　experimental　conditions　chosen　in　this　paper.　We　further　showed　that　predicted　correlations　based　on　flow　regime　could　estimate　measured　void　fraction　reasonably　well.