For decades, rapid urban expansion has led to concerns over the loss of cultivated land in rural China. Less well known is the fact that development of newly cultivated land has in fact consistently exceeded land conversion from 1999-2006. This paper provides an analytical model that makes sense of this observation, featuring scal decentralization, local governments as custodians of land use and land development, as well as a land development allowance policy put in place in 1998. The model shows how a land development allowance policy can harness and redirect the forces of urban expansion to encourage agricultural land development.