Production of small-scale DM clumps is studied in the standard cosmological scenario with an inflation-produced primeval fluctuation spectrum .
Special attention is given to the three following problems : ( i ) The mass spectrum of small-scale clumps with M \lesssim 10 ^ { 3 } M _ { \odot } is calculated with tidal destruction of the clumps taken into account within the hierarchical model of clump structure .
Only 0.1 - 0.5 % of small clumps survive the stage of tidal destruction in each logarithmic mass interval \Delta \ln M \sim 1 .
( ii ) The mass distribution of clumps has a cutoff at M _ { min } due to diffusion of DM particles out of a fluctuation and free streaming at later stage . M _ { min } is a model dependent quantity .
In the case the neutralino , considered as a pure bino , is a DM particle , M _ { min } \sim 10 ^ { -8 } M _ { \odot } .
( iii ) The evolution of density profile in a DM clump does not result in the singularity because of formation of the core under influence of tidal interaction .
The radius of the core is R _ { c } \sim 0.1 R , where R is radius of the clump .
The applications for annihilation of DM particles in the Galactic halo are studied .
The number density of clumps as a function of their mass , radius and distance to the Galactic center is presented .
The enhancement of annihilation signal due to clumpiness , valid for arbitrary DM particles , is calculated .
In spite of small survival probability , the global annihilation signal in most cases is dominated by clumps .
For observationally preferable value of index of primeval fluctuation spectrum n _ { p } \approx 1 , the enhancement of annihilation signal is described by factor 2 - 5 for different density profiles in a clump .