To study the vortex-induced vibration (VIV) and its control measures for a Π shaped deck, the aerodynamic performance of a cross-sea cable-stayed bridge was investigated through section-model wind tunnel tests. The research results show that the Π shaped deck concerned suffers remarkable VIV at low wind velocity, which exists under the structural damping ratios of 1%. Crash barrier and maintenance way railings with cylinder shape are conducive to decrease VIV amplitude, both vertical and torsional. The VIV can be mitigated via sharpening wind fairings and the vibration mitigation effect is more significant with the smaller wind fairing angle. The horizontal flow-isolating plate (HFIP), jutting out of the inner edge of the girder bottom plates, can mitigate and even eliminate the VIV effectively. Generally, within certain limits, the wider the HFIP is, the better the mitigation effect.