The behavior of ground state OH radical was studied in humid air pulsed surface dielectric barrier discharge (DBD). The validity of OH measurement in immediate vicinity of the dielectric surface was discussed using two types of laser-induced fluorescence (LIF) measurement for the first time. The results of OH measurement by two types of LIF showed that main production region of OH in surface streamer was located few dozens of um from the dielectric surface.. The OH local density in surface streamer channels was estimated to be 1×10^15 cm^-3 using decay rate of OH, which was almost the same as corona discharge one.