Methods, systems, and apparatus, including computer programs encoded on computer storage media, for message distribution based on a user mode protocol stack are provided. One of the methods includes: receiving an application service data message from a message transceiver; determining, from a plurality of user mode protocol stacks, a user mode protocol stack corresponding to the received application service data message according to correspondences between a plurality of application services and the plurality of user mode protocol stacks, wherein each of the plurality of user mode protocol stacks corresponds to an instance; and sending the application service data message to an instance of the determined user mode protocol stack, to cause the instance of the determined user mode protocol stack to process the received application service data message and to send the processed application service data message to an application service corresponding to the determined user mode protocol stack.