In the Fischer-Tropsch synthesis process, light oil with high temperature is cooled to light oil droplets and non-condensing gas. Gas-liquid (or gas-droplet) separation and operation stability are directly related to both the stability and long period running of production process. Due to its structural complexity, fluid short circuit and wax jams, Fischer-Tropsch cycle heat exchanger is difficult to meet the industrial requirements. Hence, a multi-spiral gas-liquid vortex separator with simple structure, low pressure drop and big separation capacity was designed by drawing the super-vortex quick separator from gas-solids system. The CFD method was used to study the gas-phase flow field distribution characteristics in the MSGLVS. According to its structural characteristics and pressure distribution, the separator was divided into feed pipe zone, spiral arm zone, annular zone and separation zone. The simulation results showed that more than 60% of the total resistance loss of gas flow existed in the spiral arm. Discharged from the spiral arm, the gas was separated into three streams. One was upward counterclockwise gas along closure cover, another was corresponding downward gas and the others was upward clockwise gas in the region between spiral arm and feed pipe. Transverse vortices with zero axial velocity increased the pressure drop and liquid entrainment in the annular zone. The maximum tangential and axial gas velocities were kept at |r/R|=0.972 in the annular zone and the rotation angle of upward-flowing gas was always at 37.43° relative to the vertical direction, which demonstrated the good stability of separator. In the separation zone, there was a clear interface between upward and downward axial velocities. The tangential velocity conformed to the distribution of Rankine vortex along the radial direction, which was beneficial to the separation between gas and liquid phases. All tangential and axial velocities at different positions had a good linear relationship with the inlet gas velocity. The tangential velocities at |r/R|=0.893 (in the spiral arm zone) and 0.972 (in the annulus zone ) were most sensitive to inlet gas velocity.