The simulation device is provided with a user space and a network adapter. The method comprises: a simulation device obtains a serialization command of a simulation test and configures the serialization command for a plurality of MQTT client instances, controls the plurality of MQTT client instances to package the serialization command by using a simulation protocol stack of a user space so as to obtain a simulation message, transmits the simulation message to a network adapter, and the network adapter sends said message to an MQTT server for simulation testing.