We investigated the effect of the electro- optic chromophore concentration on the space charge field formation in polymeric photorefractive composites. For polymeric photorefractive materials, the electro optic chromophore is one of the most substantial components, because it is to provide a refractive index modulation in response to the electric field and probably can act as trap which is essential part to promote space charge field inside the material. The photoconductivity was decreased as the chromophore ratio increased. However, the space charge field measured by our characterized method remains unchanged. This result can be explained that presence of chromophore may reduce the photoconductivity, but also facilitate the charge trapping process.