The performance evaluation of new and old subgrades is critical for the quality and safety of reconstruction and extension projects. It is necessary to achieve rapid and easy performance testing. In this study, a Portable FallingWeight Deflectometer (PFWD) is chosen to rapid evaluate the performance of subgrade. First, a testing area, the reconstruction and expansion project of the Hefei to Dagudian section of the Shanghai-Shaanxi Expressway, is selected. Then, the PFWD modulus Ep of resilient tested by PFWD and the corresponding water content w and compacting degree K tested by the cutting ring method for old subgrade are obtained. And the correlation relationship between Ep and w and K is established. The performance of old subgrade can be rapid obtained by PFWD. Meanwhile, for the new subgrade, the correlation relationship between Ep and bending value L, w and K is established, and the performance can also be rapid tested by PFWD. Finally, a rapid evaluation method for the reconstruction and expansion of subgrade performance was proposed, which aims to provide technical support for ensuring construction quality and safety and provides a technical reference and a theoretical basis for the prediction of similar subgrade performance.