A new extraction chromatographic technique for rapid separation of Ga in rocks using dimethylheptyl methylphosphonate (P350) as stationary phase and polydivinylbenzene (x-5) resin as supporter has been studied. The sample solution in 2.0 N HCL-3.4 N NaCl medium was introduced on the chromatographic column,Ga can be eluted quantitatively by water.The percentage recovery of Ga was 99.5-100.1%·This method is applicable to determination of O.OOOOx-0.Ox0o gallium in rocks.