Abstract: Thin glass/epoxy plates with O₂/90₂/+45₂/-45_2s were subjected to low velocity impact. To measure the property of damage in composite, we have found Mn (CH₃C00)₂/CH₃COCH₃ solution. The new liquild is cheaper and available and th, result is very succeessful. Delay technique has been used to present the pattern of damage area in composites and the relationship between delamination and impact energy. Experimental results have shown that there is a threshold value of impact energy and that a linear relationship holds between delamination area and impact energy. Observing the microsopic pattern of damage area by scanning electron micrography. We have found that the mattix cracks which are parallel to the fiber direction are caused by the tensile stresses and the delamination by the shear stresses.