NOVELTY - A steam temperature control method of steam compression machine involves dehydrating low grade coal by steam from supply process steam, supplying dehydrated low grade coal to steam compression machine (20) through process steam supply line (22), elevating temperature/pressure of compression process steam by steam compression machine, and supplying elevated temperature/pressure of compression process steam as heat sources such as evaporator (27) and heat exchanger.    USE - A steam temperature control method of steam compression machine used in modification wood-coal process.    ADVANTAGE - The method can steadily control process steam temperature easily and precisely.    DETAILED DESCRIPTION - A steam temperature control method of steam compression machine involves dehydrating low grade coal by steam from supply process steam, supplying dehydrated low grade coal to steam compression machine (20) through process steam supply line (22), elevating temperature/pressure of compression process steam by steam compression machine, supplying elevated temperature/pressure of compression process steam as heat sources such as evaporator (27) and heat exchanger, pouring and cooling remaining compression process steam which is not supplied through water pouring line (29) from supply source of water, and returning cooled compression process steam to process steam supply line by superheated steam supply line (25). The heat amount of compression process steam is computed from flow volume and temperature of compression process steam so that heat amount computed from temperature and flow volume of mixing steam which consists of compression process steam and steam after pouring water according to spraying with respect to compression process steam with respect to sum of water-pouring temperature and heat amount computed from water pouring flow volume may become equal. The water pouring is performed with compression process steam from greater than or equal to 2 places where flow volume ranges differ. The amount of diverted waters which carries out diverted water to remaining water-pouring locations according to water pouring flow volume is controlled. An INDEPENDENT CLAIM is included for a steam temperature control system of steam compression machine.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of steam temperature control system used for steam temperature control method of steam compression machine in modification wood-coal process.    Steam compression machine (20)    Process steam supply line (22)    Superheated steam supply line (25)    Evaporator (27)    Water pouring line (29)