Disclosed are a method and apparatus for determining the performance of a virtual machine, wherein the method comprises: collecting network bandwidths periodically in a chronological order (S102); recording the time for opening files on the virtual machine according to the network bandwidths collected (S104); and determining the performance of the virtual machine according to the recorded time for opening the above files (S106). The problem present in related arts that there is low accuracy in testing the performance of the virtual machine, and further the effect of improving the accuracy in testing the performance of the virtual machine is reached.