The utility model discloses a stratigraphic isolating valveof an oil-water well. The stratigraphic isolating valve comprises an upper connector, a locating sleeve, an outer sleeve and a lower connector which are sequentially connected from top to bottom, wherein two slots are formed in the inner wall of the locating sleeve, locking blocks are placed in the slots, and the two locking blocks in the locating sleeve are provided with guide-in cylinders and sliding cylinders which are connected; a rectangular slot is formed in the lower end of each sliding cylinder and is connected with a connecting rod at the lower part of each corresponding sliding cylinder through a pin, each connecting rod is located in a valve ball sleeve assembly in the inner part of the outer sleeve, each valve ball sleeve assembly is further provided with a valve ball, and a fan-shaped slot is formed in the right end of each valve ball and is hinged with the other end of the correspondingconnecting rod through a pin. The stratigraphic isolating valve of the oil-water well can be mounted on a well completion branch pipe or hung above an oil layer to be protected through a hanging packer, and the stratigraphic isolating valve can be opened or closed by a tool carried at the lower end of a working oil pipe, so that the lower oil layer can be exploited or sealed.