In order to objectively monitor and evaluate the effectiveness of land consolidation, a new method to identify filed patch data was proposed, which was based on remote sensing imagery and taking arable land polygon data as constraints. The field patch data identified by using this method not only had regional characteristics, but also considered ownership information to some extent. On this basis, evaluation index system in field and regional levels was respectively built for cultivated field patch fragmentation’s degree. Patch area, regularity, compactness and connectivity were chosen as evaluation indexes in field level and mean area, density of field patch, LAI, LSI and PAFRAC were chosen as evaluation indexes in regional level. And then the indexes in two levels were made to be dimensionless respectively. The method was applied to Guangxi hilly areas and Hainan plains. The results of experiment showed that after consolidation, the majority of comprehensive evaluation index in field level of Guangxi region was improved from 50~70 to 70~90, and that in Hainan plains was improved from 70~90 to 90~100.The comprehensive evaluation index in regional level of Guangxi hilly areas was increased from 41 to 83 after land consolidation, and that in Hainan plains was increased from 63 to 92. The proposed method for identifying field patch can support the monitor and evaluation of land consolidation projection aimed at land fragmentation, no matter study areas located in hilly areas or plain areas. Hence, the research result can provide support for remote sensing monitor and evaluation in land consolidation areas and remote sensing discerning of well-facilitated farmland.