Dynamic recrystallization is characterized by cyclic events nucleation and grain growth during plastic deformation. The evolution of grain size distribution in dynamic recrystallization was investigated by a stochastic model of nucleation-and-growth. Scaling relations representing characteristic grain size and recrystallization cycle were derived from nucleation rate I and growth rate R'. The grain size evolve from an initial distribution to a steady-state one that is approximated by a log-normal distribution. A universal relation between deformation conditions (i.e., stress and temperature) and the steady-state grain size were formulated for recovery creep of minerals.