A surface defect detection system is proposed for mobile phone screen glass. This system achieves 94% in sensitivity and 97.33% in specificity. The proposed system takes approximate 1.6601 s to detect a MPSG. The detection accuracy and speed can meet the needs of online detection for MPSG. Compared with other methods used in the experiment, the proposed improved fuzzy c-means can segment the surface defects in MPSG more accurately.