Cross-waveguide is one of building bl ocks widely employed in electro-optical circuit board (EOCB) light-guiding lay er.To characterize the dependence of cross-waveguide loss on waveguide width,pe rpe ndicular cross-waveguides with different widths of 5μm,10μm,20μm,30μm and 40μm have been manufactured by ion-exchange (IE),and subsequently el ectric field-assisted ion-migration (FAIM) in glass substrate.Crossing loss of these waveguides has been characterized on these waveguides.Res ults show that the crossin g loss of waveguide on glass substrate exhibits significant dependence on wavegu ide width:with waveguide width decreasing from 40μm to 5μm,the crossing lo ss o f glass-based waveguide decreases from 0.071dB/cross to 0.019dB/cross.The dep endence of crossing loss on optical waveguide provides a new dimension for the o ptimization of EOCB.