The distribution of wind velocity in the coastal area is very complicated, and the study of the law of wind velocity is important for the development of the coastal wind field. Based on the average wind velocity data from July 1, 2009 to June 30, 2011 of 38 meteorological observatories within 40 km area along the coast of Jiangsu, the analysis of the attenuation law of the average wind velocity was carried out by using the Rotated Empirical Orthogonal Function (REOF) model, and the coast area was further divided into the south and north areas. The average wind velocity is e exponentially decaying from the coast to the inland. On this basis, the spatial distribution equation for the average wind velocity in the south and north areas was derived, and the fitting accuracy test and reliability analysis were carried out. The results show that the impact range of the underlying surface difference is not completely positively correlated with the wind velocity in the coastline, but there are critical values, i.e. 18.2 m·s^-1 for the south area and 14.6 m·s^-1 for the north area.