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; a simulation message generating module for acquiring a plurality of simulation instructions corresponding to the at least one simulation action tag and comprising starting and ending time points of emotional features and combining the simulation instructions with the message content to generate a simulation message; and a simulation instruction database for recording at least one simulation instruction corresponding to each of the at least one simulation action tags and for sharing the customized simulation instructions with other users; 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 and for receiving customized simulation instructions from the user device and uploading the customized simulation instructions to the simulation instruction database.