Abstract: Reliability of the brazing process in ceramic package manufacturing is affected by the hot-cutting defect on ceramic surface. This paper characterizes and estimates the rarely mentioned defects formed during hot-cutting process of alumina green tape. Surface and edge morphology of hot-cutting surface is examined by 3-D optical microscope and scanning electron microscope(SEM) before and after sintering. Based on Griffth fracture criteria, three-point flexural test is utilized to estimate the fracture dominated by defects on different surfaces. Multiple comparison is conducted to test the difference between fracture statistics governed by defects on different surfaces. Observation shows the hot-cutting defect is new defect existing on the cutting surface with completely different morphology, and results of multiple comparison indicate the edge hot-cutting defect is more dangerous than the intrinsic defect in ceramic and is prone to degrade the reliability a lot in the assembling process.