A new type of intra-tube sealing device for stratified pumping was designed and manufactured in order to meet the requirements of water sealing in stratified pumping test and observation. This new sealing device has the advantages of simple structure and can be conveniently processed with on-site materials with reliable sealing effect; the shortcomings of traditional sealing method are overcome, the upper and lower aquifers can be effectively isolated to prevent the water mixing flowing of upper and lower aquifers. Thus, rapid stratified water sealing inside pumping tube in a same well can be realized, which ensures the operation of stratified pumping test.