Abstract: The relation between the zonal averaged non-thermal wind, the instantaneous mean meridional cell and the change of zonal circulation is investigated synoptitally and statistically for eight cases which are selected from the winter half year of 1916-77.Preliminary results are obtained. When the rate of change of zonal averaged non-thermal wind, denoted by (∂u'T/∂t), is a large negative value there exists an indirect meridional circulation in middle latitudes. Under such situation, planetary waves tend to decay and zonal circulation tends to intensify. In contrast, when (∂u'T/∂t) is a positive, there exists a direct meridional cell Under this condition, planetary waves will develop and zonal circulation decreases. Finally, the above results are discussed by making use of the conception of adjustment of thermal wind.