1. A data collection method, comprising: a network management device collecting data files to be processed reported by a network element device; assigning the data files to be processed as a plurality of tasks; and adding the plurality of tasks into a task queue and extracting tasks from the task queue one by one for processing; wherein the step of assigning the data files to be processed as a plurality of tasks comprises: evaluating a total quantity or capacity of the data files to be processed; evaluating local calculation ability; obtaining local configuration parameters; calculating task payload of each thread according to the quantity or capacity of the data files to be processed, the local calculation ability and the configuration parameter; and assigning the data files to be processed as the plurality of tasks based on the task payload; wherein the local calculation ability comprises: local CPU processing speed and memory capacity, and the configuration parameter comprises: a number of threads and maximum activation time of the threads; wherein the task payload of each thread is equal to the total data quantity or capacity divided by a number of processing batch and then divided by the number of threads; wherein the number of processing batch=Max (the total data CPU processing time/(the number of threads*the maximum activation time), the total capacity of the data/memory capacity), wherein, Max represents to take a maximum; wherein the total data CPU processing time is equal to the total quantity or total capacity of the data files to be processed divided by the CPU processing speed.