Chiangrai city is located in the northern part of Thailand and is a high risk area to be affected by the earthquake ground motion. Because the city is laid on the soft sediments of a alluvium deposits of Kok river, these soils underneath the city can amplify ground motions thereby increasing earthquake damage. The ground motion amplification of soils can be estimated by using their averaged shear wave velocity down to 30 meters (Vs(₃₀)). Amplification of soils can be inferred from shear wave velocity that the soft soils with the low Vs values have the ability to expand ground vibration more than high Vs values. Consequently the main objective of this study is to create the soil classification map of the city using the (Vs(₃₀)). In this study, we use the MASW (Multi-channel Analysis of Surface Wave) techniques to determine Vs of soils. We collected seismic data over 30 locations covering in 5 soill units. We then calculated the Vs(₃₀) in each test site and used it to classify the soil classes based on the recommendations of the 2003 National Earthquake Hazards Reduction Program (NEHRP). Finally we developed the NEHRP site classification map of the study area. The results reveal that the Vs(₃₀) values of the near mountain zone and the natural levee can be classified as site class C with the average Vs(₃₀) of 418 m/s. However the northern valley plain and eastern floodplain which cover most of the study area are classified as site class D with the average Vs(₃₀) of 338 m/s. Based on the site-classification map, we can conclude that the main part of the study area is under substantial risk of soil amplification.