Abstract: In this paper, the steady 3-Dstream field and the corresponding Pressure and temperature(density) field are obtained from the equations describing the meso-scale vortex in the geophysical fluid.The 3-Dvelocity fields construct anonlinear autonomous system in the physical space.It is shown that the centres of the cyclonic(anticy clonic) are low pressure(high pressure) with the horizontal convergence(divergence) motion in lower levels and the results are just the contrary in upper levels.So there exists the 3-Dspiral structure in the meso-scale vortex, there are in conform fairly well with o bservations.It implies that the rotation of earth and viscosity of fluid play an important role in the spiral structure in order to ensure the mass conservation.