This paper used field observation method,interview method and questionnaire method to investigate planting trees on abandoned farmland in T town of Hebei province in order to explore the causes of planting trees on abandoned farmland.The results showed that abandoned farmland was caused by separation of labour force and land,technological restriction of land management and the game between non-agricultural management and agricultural management.And the causes of planting trees on abandoned farmland are economic motivation,external influence and systematic conditions.This paper put forward such countermeasures of dealing with planting trees on abandoned farmland as improving the household contract management system to prevent nonagricultural use of farmland,establishing an effective mechanism for transfer of agricultural land to encourage the orderly flow of agricultural land,giving full play to collective power to reconstruct and repair irrigation and water conservancy facilities,attaching the importance to village officials to restrain and dredge planting trees on abandoned farmland etc.