On an OpenStack cloud platform, a server may simultaneously run more than a dozen virtual machines, which requires high system network I/O performance. Therefore, the efficiency of I/O virtualization is important for the improvement of network performance on OpenStack cloud platform. In order to improve the overall network performance of the system, introducing SR-IOV technology into the OpenStack cloud platform is an option. The influence of SR-IOV technology on network I/O performance of OpenStack cloud platform is tested by contrast experiments. Finally, the experiment results show that, after the introduction of SR-IOV technology, the I/O virtualization performance of computing nodes in OpenStack cloud platform have increased by about 50%.