Abstract: The cultivated land fallow system has been an important measure to implement the strategy of “food crop production strategy based on farmland”, which is of far-reaching significance for ensuring the food security and achieving the sustainable development of the agriculture. This paper is based on the connotation and technology about spatial allocation of the cultivated land fallow, to solve the low-efficiency and profit-loss problem due to the unreasonable spatial allocation of the fallow land. This paper takes Songtao County, a severely degraded area and one of the first batch of pilot fallow counties of Guizhou Province in China, as an example to illustrate how to diagnose and identify fallow land by using comprehensive health evaluation method,and to select different fallow land according to different requirements. The research results indicate that: (1) The essence of spatial allocation of the cultivated land fallow in the broad sense is to optimize the combination of the scale, the distribution, the time sequence and technical pattern of the fallow land, in order to realize the mocro-control of “quantifying, locating, sequencing and technology-selecting of the fallow land”. (2) The important basis of spatial arrangement in the fallow regions is the diagnosis and identification of the fallow cultivated land based on comprehensive health evaluation of the cultivated land, which is determined by the quality goal and production capacity goal of the cultivated land; the essence of spatial arrangement in the fallow regions is spatial testriction, with area concentration and contiguity as its main trestriction. (3) The health condition of the cultivated land in Songtao County is at the average level, it’s of great potential to carry out the fallow land system and it’s suggested that dry land is of greater potential than paddy fields, combining moderate fallow measures with prioritized fallow measures. (4) The fallow area of the paddy field is mainly distributed in northeast, west, and southern towns; the fallow area of the dry land is distributed in entire county, mainly distributed in the eastern and central part of the county.