The invention discloses an application of solid micron powder insoluble in water. The application of the solid micron powder insoluble in water includes that firstly, the powder and plant seeds are subjected to seed dressing; and secondly, the powder and a fertilizer of a plant are mixed to be applied as a base fertilizer or topdressing. The grain size of the powder ranges from 2.5 mu m to 50 mu m; and the powder is selected from at least one of sedimentary rock, volcanic rock, metamorphic rock, calcium carbonate, calcium sulfate, magnesium carbonate, ferric oxide, ferroferric oxide, iron pyrite, haematite, magnetite, wood coal, graphite, carbon black, brown coal, rock phosphate, zeolite, attapulgite, mica, zinc oxide, cupric oxide, quartz sand and manganese dioxide. The solid micron powder insoluble in water is applied to planting and growing processes of the plant, so that the plant growth can be promoted, the yield is increased, and the product quality is improved.