The surface wave magnitudes of 1755 earthquakes from 1985 to 2003，determined by the Luoyang seismic station with the same surface wave magnitude formula as the one China Earthquake Networks Center uses，are compared with the CENC earthquake catalogue． The result shows that，the surface wave magnitude deviation of Luoyang seismic station is closely related to the epicentral distance． The magnitude deviation is from smaller than 0. 1 to larger in the epicentral range of 1°≤Δ≤130°; it is 0. 2 ～ 0. 3 larger in the range of 20° ＜ Δ≤130°; the deviation is 0. 2 larger in the range of 130° ＜ Δ≤180°．