This research is focused on the investigation of impact strength and the microscopic observation of material behavior of glass fiber reinforced polypropylene in solid phase forming. The fiber weight per-centage of the composite materials was 20%, 30% and 40%. The solid-phase formed specimens were pre-strained to 10%,20%. and 30% strain levels. The forming temperatures of specimens were $100^{circ}C$, $125^{circ}C$ and $150^{circ}C$. Izod impact test was performed with unnotched specimens. With increasing the glass fiber content ; the impact strength was increased