The invention discloses a network data communication method for an intelligent substation. An extendable novel network data package storage format is adopted; a data file is composed of three parts, namely, a head file domain, a monitoring network domain and a data package domain; a user-defined extended information item is supported by each part; the third-party information matched with an analysis data package is embedded into the data file; when the data file is subjected to the electric system data analysis, the third-party file is not dependent and an independent data package file can finish the data analysis; the data file can be used for storing the network capture package data of a plurality of network interfaces; the requirement for the storage and offline analysis for automatic communication network data in the intelligent substation is met.