Ferrofluid composites consist of non-magnetic polystyene particles dispersed in a kerosence-based ferrofluid. Their birefringence and dichroism in applied magnetic field were measured. In experiments it was found that under the condition of the same magnetic field, 1) the birefringence of ferrofluid composites is smaller than that of pure ferrofluid; 2) the linear dichroism of the composite samples is stronger than that of the pure ones. With a simple theoretical model, the results are explained.