In order to develop advanced flexible sealing technology for aviation, the brush sealing structure of GH4169+Haynes214 brush wire was developed by electron beam welding. The effects of different welding processes on the weld formability, microstructure characteristics, microhardness, and sealing performance of the welded joint were studied. The results indicated that the use of electron beam welding technology can achieve well-formed welded joints, without crack and pores. The microstructure of the weld joint was a dendritic crystal with short transverse dendrites and long main axes, mainly composed of γ, γ' and γ'' (Ni₃Nb), and eutectic structure is formed between short transverse dendrites (γ+ Laves). The carbides in the fusion line region were grown and agglomerated at grain boundaries under thermal cycling. The microhardness of welded joint was approximately symmetrically distributed, with an average hardness of approximately 435HV in the weld area, which was smaller than base metal (approximately 540HV). Because the weld area was mainly Haynes214, which contained high Ni and Al content. During the welding solidification, Haynes214 was mixed with GH4169 alloy elements, resulting in changes in microhardness caused by differences in the microstructure of the solidified welded metal. The leakage rates of the brush sealing structure were less than 20 g/s at room temperature (20 ℃) and high temperature (403 ℃). At room temperature (20 ℃), the leakage coefficient was stabilized around 0.006, which was less than the expected leakage coefficient of 0.007. When heated to 403 ℃, the leakage coefficient gradually increased with the increase of pressure, and finally was stabilized around 0.004, indicating that the brush seal structure has excellent sealing performance and can be promoted and applied in aerospace engines.