It is the purpose of this investigation to clarify the relation between volume resistivity and stress luminescence of GFRP (Glass Fiber Reinforced Plastics). The volume resistivity decreases as the moisture content in GFRP increases. The tensile test was used in this experiment and the luminescence was detected by a photo-electron multiplier.The results obtained are as follows:(1) The intensity of luminescence per unit area on the delamination increases as the volume resistivity increases.(2) The appearance of first luminescence is delayed as the volume resistivity decreases.(3) The intensity of the luminescence per unit area decreases as the appearance of first luminescence becomes later.Furthermore, a simulation test of the luminescence was tried to obtain the amount of energy which is transformed to the luminescence.As the result, 5∼30×10-6[J]is transformed to the luminescence.