The invention provides a construction method for a simulation system based on a hot-rolling L2 process control system. The method comprises the steps: S1, equipment selection of the simulation system,network design and application work platform integration; S2, deployment of all regional subsystem modules of the simulation system, wherein each regional subsystem includes a heating furnace system,a rough rolling system, a finish rolling system, and a laminar cooling system; S3, design of a parallel mode of the simulation system and processing of a parallel message; S4, data management of a simulation process, installation of database software, management of process data; S5, design of an L2 communication system and an L1 communication interface, and achieving of a purpose that the simulation system receives L1 actual strip steel data in real time. The simulation system of the invention can provide a stable, reliable, real and effective test environment and can ensure the successful use of the functions once, and the new function can be directly debugged and tested on the simulation system, and the rolling line production is not affected, thereby reducing the halt production and steel waste of a rolling line, and improving the progress of functional use.