We investigate the absorption, stimulated emission cross section and potential laser parameters of Yb3+ doped geano-silicate glasses (GSY glass). The emission cross section is evaluated by using the measured absorption spectra and the principle of reciprocity. It is found that Ybs+ in GSY glasses has high stimulated emission cross section of 0.5-0.65pm2 near 1020nm and exists long measured fluorescence lifetime of 1.20-2.00ms. Compared with other glass hosts, the GSY glass exhibits excellent general spectroscopic properties for Yb3+-doped doublecladding fibres.