Under the integrated influences of global climate changes and overgrazing, China rangeland has degraded over recent years. Maduo County locates in the Source Region of Yellow River and its rangeland has experienced expansive degradation. The government of Qinghai Province launched an eco- immigration policy in 2004. In order to analyze the responses of herd families to the eco- immigration and the reasons for these responses, the authors used three periods MSS and TM images for recent 25 years and interview survey data of 144 herd families in recent two years, getting the following results: (1) the rangeland had degraded extensively for recent 28 years; and (2) the immigrant families were mainly composed of the old, with little or no livestock. What's more, the percentage of immigrant households that share one rangeland certificate with parents or brothers in the immigrant family was 54.5%. Therefore, it is hard to greatly decrease the overgrazing degree through eco- immigration with those previous characteristics of eco- immigrant family structure.