Through the field surveys and interpretation of air photoes in different stages, this paper studied the land reclamation activities by human beings the loessal hilly areas in 30 years. Based on the obtained preliminary information and the characteristic of soil erosion and siltation of reservoirs, this paper also analyses and discusses the time variations and spacial distributions of waste land reclamation activities and its effects upon soil erosion and sediment production, the base was given for discussion of the relation between human activities in production and acceleration of soil erosion.