The Concorde MicroPET Rodent R4 system designed by Concorde Microsystems Inc. is the dedicated positron emission tomography (ECT) for studies of rodents. The scanner has 32 detector rings and a 120mm animal aperture. The transversal field of view(FOV) is 100mm, and the axial FOV is 78mm. The spatial resolution at the center of FOV is smaller than 1.8mm. This paper designs a series of experiments to evaluate the performance parameters (spatial resolution, sensitivity, scatter ets.) of the scanner. In the center FOV the transversal spatial resolution is 1.9mm, the axial spatial resolution is 1.88mm. The absolute sensitivity of the system is 39.88 cps/kBq for an energy window of 250KeV-750KeV. For the same energy window the 2D-reconstructed scatter fractions is 50.6%, the 3D-reconstructed scatter fractions is 32.3%.