Research on carrying capacity as an important indicator describing the state of regional urbanrural systems is quite important. Based on an analysis of urbanrural system elements characteristics and mechanism, mathematical models were established to evaluate regional comprehensive carrying capacity and development expenditure level. These models were applied to a case study of Hainan Province, P. R. China, using statistical data from 1995 to 2005. The conclusions are as follows: (1) During this period, the carrying capacity of the regional urbanrural system in Hainan fluctuated, and the capacity was overloaded from 1995 to 1998, under loaded from 1999 to 2001, and overloaded again from 2002 to 2005. (2) The degree of coordination between the regional natural and socioeconomic carrying systems is 0.60, three times the regional multiple carrying capacity. Both the socioeconomic and natural carrying capacities rose unsteadily, averaging 0.30 and 0.11, respectively. (3) The contribution of various carrying factors to regional multiple carrying capacity is quite different. Carrying capacity factors include socioeconomic development, human resources, imports, environmental and resource possession. Their average rates of contribution were 31.40%, 22.71%, 18.79%, 13.64% and 13.45%, respectively. (4) From 1995 to 2004, economic development expenditures were the principal part of all regional expenditures, the contributing 61.88%. In 2005, export expenditures exceeded economic development expenditures, becoming an important part of the all regional expenditures.