Abstract: Based on field experiment，this paper gives a brief introduction of the mulching effects on soil water distribution and depletion under drip irrigation，the growth of potato under drip irrigation and furrow irrigation，etc．The results show that the plastic mulch can reduce the evapo ration through soil surface and maintain relatively high soil moisture in the topsoil during the early growing period of potato． However，transpiration has become the main way of soil water depletion during the later period and makes the mulching effect on the reduction of evapo ration insignificant．When the temperature is high，the plastic mulch can res train the growth of potato．