The relationship between surface mount component solder joint section area and solder defect, section height and solder defect, contact angle and solder defect were studied respectively. By using dividing method, the contour data of solder joint center section was obtained and the shape parameters of solder center section were calculated. By using the least-square method, regression analysis was carried out, the correlation coefficient between the input vectors and solder defects was calculated, which can be used to discriminate the correlation between the selected input vectors and the solder defects. The results show that: the section area, section height and contact angle have related with solder quantity, contact angle also has relationship with solder joint wet ability.