Abstract: On account of the problem of the same diameter sealing and stratified pumping test in a hard rock borehole with very small water-sealing ring gap (only 3 mm) unsolved by traditional construction procedures, taking the hydrogeological parameter well located in Shanxi Province as the research object, the in-situ and laboratory comprehensive tests are employed to implement the research on the construction process of same diameter water sealing plans, materials, technology, as well as the stratified pumping test. Results show that, (1) as for the water sealing device with the same diameter, the outer of the water sealing ring gap is increased from 3 mm to 8.5 mm by special design and manufacture of “cut out and shrink in” to solve the problem of same diameter water-sealing under the situation of extremely small water sealing ring gap, which performs well via the pumping test inspection. (2)Based on the series of tests research outside the bore hole, the custom-made “sealing material” and selected “water sealing combination” have strong adaptability with the hole, and the implementation of down-pipe goes rather smooth with low risk. (3)The stratified aqueduct is specially designed, on which the concatenated isolation sealing rubber ball fit well with the conical water isolating joint set in the waterproof casing pipe. The water sealing is reliable, and two sets of independent aqueduct are formed to meet the stratified pumping test of the upper and lower aquifers. The research results can provide reference for the same diameter water sealing or stratified pumping test of similar hydrogeological parameter wells.wells.