Aiming to clarify the interaction mechanism of gas-liquid cross-zone rotating flow in the rotational flow zones and packing zones of composite tridimensional rotational flow sieve tray (CTRST), the CTRST was investigated based on a dual Eulerian two-phase flow simulation method. The flow interaction between the two zones was described by the volume flow ratio of the gas and liquid phases, and the interaction mechanism of liquid phase distribution, pressure and velocity fields under the interaction between the two zones was analyzed, and compared with that of a single rotational flow configuration tray. The results indicated that the mass flow rate ratio of gas-liquid phase in the rotational flow zone always accounted for over 60%, the axial cross-section where the maximum value of the gas-liquid volume flow ratio was located transforms with the change in gas-liquid volume. The cross-section of the maximum gas-liquid phase volume flow ratio rose from Z=25 mm to Z=10 mm as Lw increased, and decreased from Z=25 mm to Z=40 mm as Fs increased. The packing zone had a strong buffering effect on the rotating flow. It significantly slowed down the trend of pressure reduction in the rotational flow zone, and the addition of packing did not affect the balance of pressure drop between the two zones. The structures of the packing zone and the rotational flow zone had a relatively uniform blocking effect on gas-liquid two-phase flow, and the pressure drop distribution was relatively uniform. There was a transition point in the rotational flow zone that changed the direction of the rotating flow, and the position of the transition point moved inward axially towards the inner cylinder. Compared to a single rotational flow configuration tray, the inward shift of the CTRST transition point improved the liquid holding capacity of the rotational flow zone and promoted gas-liquid interaction flow between the two zones.