由於經濟發展，使得人顯對土地的需求增強，故須加強集約使用，若按集約強度而言，約可分為非建築用地與建築用地，土地使用若任由市場運作，非建第用地必能逐漸轉用為其他較集約的使用，惟因公共財與外部性的問題，使得公共部門介入土地市場，遂進行各種使用分區的規劃，若規劃制度過於懂化，致使非建築用地無法轉用，必使地價畸形上灘，導致資源的錯誤配置，本文認為公共部門應善用其規劃權與課稅槽，以保存適量的建第用地，必減輕地價的上漲。

According to its utilization， land can be classified into rural and urban ones. As a result of economic development， rural land will be converted to urban land gradually. Due to the problem of public goods and externalities， the public sector has to intervene this process of conversion in order to achieve maximum social welfare. However， there will be a shortage of urban land and land price will be soared if the intervention from the public sector is too rigid. We suggest that police power and land taxation can be used to alleviate the shortage of urban land， and as a result， urban land price will not be raised drastically.