Based on the data analysis of the wind speed,wind direction and temperature observedon Tianjin tower during 8 months in the winter season of 1990-1992,the characteristics ofwind shear in the boundary layer below 250m in Tianjin are given,such as the temporal andspatial variations of the index pin the power law of the wind profile,the frequency distribution of the wind shear in different layers and different time intervals,the relation between thewind shear and stability. The vertical distribution of wind in the tower layer over the city ispresented. The variations of the wind shear and temperature during the passage of cold frontare also analysed.