The specific features of diffusion-assisted geminate radical pair (RP) recombination in high magnetic field is analyzed in detail. It is shown that the dependence of the recombination yield R on the intraradical magnetic interaction (A) over bar (hyperfine interaction, etc.) significantly depends on the parameter xi similar to((A) over bar /D alpha (2)), in which D is the diffusion coefficient and alpha (-1) is the characteristic length of the spin exchange interaction. Simple formula, accurately describing the dependence R((A) over bar) over a wide region of parameters of the system, is proposed and thoroughly discussed.