The third synchrotron radiation facility provides a brilliant source for X-ray imaging taking the advantages of its monochromaticity and tunability. For low-Z materials, X-ray grating based on differential phase contrast imaging can provide higher sensitivity than conventional X-ray imaging. Combined with computed tomography (CT), it also can realize three-dimension high resolution imaging and measurement of refractive index. A set of X-ray grating based on imaging system is installed at the X-ray imaging and biomedical application beamline at Shanghai Synchrotron Radiation Faclity. Based on this system, three kinds of contrast including absorption, phase and scattering can be retrieved separately based on a single set of projections. According to test results for the standard sample of three different kinds of polymer, the refractive index decrement can be achieved. All these results demonstrate that the established X-ray grating imaging system can provide multiple contrast imaging and may play an important role in the nondestructive and quantitative imaging to biomedical and material samples.