Nonlinear dynamic behavior of hot spot formation on tungsten (W) material surfaces is numerically investigated by introducing a transient heat pulse into the local area of the hot W sheet immersed in high heat flux plasma. It is found that the formation and development of hot spot depend not only on plasma parameters (plasma heat flow, plasma potential variation) and the energy and time scale of heat pulse but also sensitively on electron-emission characteristics of the tungsten surface as well as the size of hot spot in a nonlinear way. (C) 1999 Elsevier Science B.V. All rights reserved.