The paper shows the main surface defects of cold rolling automobile sheet in BX Steel.The main surface defects are unusual defects.The typical familiar defects are sliver and punctuates that are on the rolling direction.The inclusions of steel-making and scales of hot rolling process are the main causes of defects.They are the biggest problems puzzle cold rolled automobile sheet surface quality,and are the burning issues of BX Steel.We classify and analysis the defects.We observe the panorama of surface defects using portable video microscopy apparatus,and clean the sample using ultrasonic shaker,analysis the defects pattern and chemical composition using scanning electron microscope.At present the primary defects that impacted cold rolled automobile sheet quality are dark sliver defects.We control the steel-making and hot rolling process aiming at the cause and position of defects making.We fine control the operating of steel ladle,gating,casting system and continuous casting machine in steelmaking process.The scale defect is reduced by controlling furnace,high pressure water descaling system and finish mill descaling in hot rolling process.Alone with the reforming and renewing of equipment,gathering producing experience,the cold rolled automobile sheet quality made in BX Steel is upgrading gradually. The paper shows the main surface defects of cold rolling automobile sheet in BX Steel. The major surface defects are unusual defects. The typical familiar defects are sliver and punctuates that are on the rolling direction. The inclusions of steel-making and scales of hot rolling process are the main causes of defects. they are the biggest problems puzzle cold rolled automobile sheet surface quality, and are the burning issues of BX Steel. We classify and analyze the defects. We observe the panorama of surface defects using portable video microscopy apparatus, and the sample using ultrasonic shaker, analysis the defects pattern and chemical composition using scanning electron microscope. At present the primary defects that impacted cold rolled automobile sheet quality are dark sliver defects. We control the steel-making and hot rolling process aiming at the cause and position of defects making.We fine control the operating of steel ladle, gating, casting system and continuous casting machine in steelmaking process.The scale defect is reduced by controlling furnace, high pressure water descaling system and finish mill descaling in hot rolling process. Alone with the reforming and renewing of equipment, gathering producing experience, the cold rolled automobile sheet quality made in BX Steel is upgrading gradually.