The deep dehydration principle of GDY series steel belt type filter press: the strong steel belt supports the filter medium and provides line tension of 300Kg/cm, to improve the impelling force of material filtration, and greatly reduce the moisture content of filter cake, thus reaching the purpose of deep dehydration. Integrated with merits of high-pressure diaphragm filter press and general belt filter, the equipment may realize high press dehydration and can also operate continuously, therefore, it is an ideal solid-liquid separation equipment with large production capacity, high filter cake dryness and low running cost.