1. A method for implementing performance management, comprising the following steps of: obtaining, by a network management system, a performance management information model which is used for describing related information of all performance data that need to be collected; instantiating, by the network management system, the performance management information model according to a current applied telecommunication network to obtain a performance management information model instance; and collecting, by the network management system, the performance data according to the performance management information model instance; wherein, the performance management information model contains network element type description information, network element positioning information description information, network element measurement type description information and measurement type counter description information; and wherein, the step of instantiating, by the network management system, the performance management information model according to a current applied telecommunication network to obtain a performance management information model instance is: instantiating, by the network management system, the network element type description information, the network element positioning information description information, the network element measurement type description information and the measurement type counter description information respectively according to the current applied telecommunication network to obtain a network element type instance, a network element positioning information instance, a network element measurement type instance and a measurement type counter instance.