The invention provides a polished rod sealing device. The polished rod sealing device comprises packing sealing boxes, packings, an adjusting piece and a static sealing part, wherein the packings are arranged in the packing sealing boxes; the static sealing part is connected with the lower end of the packing sealing box located at the lowest end; the adjusting piece is used for adjusting the fastening degree of the static sealing part and a polished rod; the static sealing part comprises a fastening position and a releasing position; the static sealing part fastens the polished rod when in the fastening position, and a gap is formed between the static sealing part and the polished rod when the static sealing part is in the releasing position. The static sealing part is arranged, so that when one packing is required to be replaced, all that is required is to perform seal fit of the polished rod and the static sealing part, pressure can be stopped at the static sealing part, the packing can be replaced by a worker under the pressure, the safety of oil producing operation is guaranteed, and the production efficiency of an oil well is improved.