Cosmic dusts with black colour, strong magnetism and average grade of 0.206mm (from 0.1 to 0.4 mm) has been first found in the artificial pla- cers from Dajishan granite, The shapes can be divided into three groups; sphere, ellipse sphere and irregular, According to the compositions, two types, iron and silicate spherules, are distinguished, The main minerals are as follows; wustite, magnetite, a-Fe, Cu, albite and K-feldspar. The fabrics are skeleton crystal, brain-pattern, lace-Iike, pearl-string etc, Chromite, SiC and whitneyite also exist in the artificial placers, All these imply that the particles are of cos mic genesis derived from exterrestrial space, We suggest that; (1) the cosmic dus tis products of nonequilibrium crystallization under the condition of low oxy- gen fugacity, high temperature and rapid drop in temperature; ( 2 ) the source of cosmic dust has a strong relation to the genesis of Dajishan granite, the co- smic dust may be the residules of strata from which granitic magma is origi- nated; (3} cosmic dust in granite can be used as an indicator of genesis study of granitic rocks.