We investigated the dependence of the grating formation on temperature in photorefractive polymeric composite, especially the index contrast of the grating. For photorefractive polymeric materials, temperature is one of the most important factors together with the external electric field, because it is closely related with photogeneration efficiency, carrier mobility, electro-optic coefficient tensor and so on. The diffraction efficiency of the photorefractive polymeric composite decreased with increasing the temperature, and it could be explained with the magnitude of space-charge field and the electro-optic behavior at various temperatures.