1. A system for simulating an expression of a message, comprising a network platform end and at least a user end, wherein the network platform end communicates with the at least user end through a communication network, and wherein the network platform end comprises: a message capturing module for capturing a user message; a feature analyzing module for performing a characteristic analysis on a message content of the user message so as to mark at least one simulation action tag on the message content; and a simulation message generating module for acquiring a plurality of simulation instructions corresponding to the at least one simulation action tag and combining the simulation instructions with the message content to generate a simulation message; and the user end comprises: a user device comprising a network module for receiving the simulation message through the communication network and a driving module for outputting the message content and the simulation instructions contained in the simulation message; and a simulation device for receiving the message content and the simulation instructions from the driving module and for playing the received message content and executing the corresponding simulation instructions.