The effects of ultrasonic deoiling temperature and concentrations of emulsifier on the surface quality of U shaped copper channel treated by ultrasonic cleaning were studied. Results show that emulsifier with the temperature of 50 ℃ and the volume fraction of 5% can effectively remove the oil and dirt on the surface of U shaped copper channel;Furthermore,the effects of flux on the U shaped copper channel surface state were also studied. Results show that the flux of"300 g/L stannous chloride + 15% nitric acid + 3% isopropyl alcohol"has the best welding effect. Based on the degreasing experiment and fluxing experiment,soldering experiments under different hot tinning temperature( 360 ～500 ℃) were conducted. Results show that when the hot tinning temperature is ranging from 400 ℃ to 440 ℃,wire surface quality is good,without any tin-lump,black spots,burrs and other surface defects. At the same time,wire bonding force between core wire and Cu channel and residual resistance ratio can meet the requirements.