Abstract: Horomill is one of the advanced cement grinding equipments in cement industry it incorporates energy savings of roll press, reliability of ball mill. In this papen, the service principle, theory formulary design of Horomill are analyzed and deduced. The new stress analysis model of the Horomill was established. Based on the partitioning, two different sections of fragmentation and compaction, the stress state and theory formulary of main parameters for Horomill design were deduced. Combined with the industrial test results, formulary of main parameters for Horomill design was given.