A method and corresponding system for implementing Virtual Network Function (VNF) performance monitoring is provided. The method includes that: an Element Management (EM) receives a threshold policy of a VNF performance monitoring threshold sent by a Network Management (NM) or an Operation Support System (OSS); the EM acquires related information about virtual resources after the VNF is scaled up/down; and the EM sets a new performance monitoring threshold for the VNF according to the threshold policy and the related information about virtual resources after the VNF is scaled up/down, and the performance monitoring threshold includes at least one of a scale up/down threshold and a performance warning threshold.