The utility model discloses a device for removing hydrogen sulfide in associated gas in an oil well. The device comprises a sealed box body, a gas inlet pipeline and a gas outlet pipe, wherein the sealed box body is used for containing a working fluid; the gas inlet pipeline is used for introducing the associated gas in the oil well into the sealed box body to react with the working fluid so as to remove the hydrogen sulfide; the gas outlet pipeline is used for introducing the associated gas subjected to hydrogen sulfide removal out of the sealed box body; the interior of the box body is a space for containing the working fluid; the box body is provided with a gas inlet pipeline interface and a gas outlet pipeline interface, the upper part of the box body is provided with a chemical filling port and the lower part of the box body is provided with a liquid discharging port; the gas inlet pipeline extends into the box body through the gas inlet pipeline interface on the box body and extends to the bottom of the box body so as to be arranged horizontally; the gas inlet pipeline horizontally arranged at the bottom of the box body is provided with gas outlet holes; the gas inlet end of the gas outlet pipeline extends into the box body through the gas outlet pipeline interface on the box body and is positioned above a working fluid surface. The device disclosed by the utility model has the advantages that toxic gas (hydrogen sulfide) in the associated gas in the oil well can be removed and the problems that natural gas is wasted and the environment is polluted also can be solved.