Rapid deterioration of structure and functional properties in agroecosystems has intensified the need for research on agroecosystem health. Assessing agroecosystem health at plain scale has been rarely reported. Agroecosystem Health investigating requires a holistic approach based on its biophysical, socioeconomic and human community dimensions. In order to assess agroecosystem Health in Mashhad plain, this research was conducted for the period of 1982 to 2012. The assessment necessitates the selection of indicators which represent various aspects of the agroecosystem. The purpose of this study was to establish a conceptual framework that facilitates the assessment of Agroecosyetem Health. The first step was to develop a set of indicators. Data on structural, functional, and organizational criteria were collected from official documents and statistics and also questionnaires. We assess these indicators for 30 years in Mashhad plain from 1982 to 2012 in 5 years periods. We defined and described some health indicators for first time, these indicators plays an important conceptual role in evaluating of Mashhad plain agroecosystem health. Results showed that from 1982 to 1997 Health Index (HI) decreased and the lowest HI was in 1997 and after that trend of HI was improved. Structural and functional criteria were increased but organizational criteria was decreased and then finally, situation of agroecosystem health had been better in Mashhad plain. Sensitivity analysis showed that functional criteria had the highest correlation with HI. To improve the HI in short term, the most effective parameters would be functional indices such as chemicals, water use efficiency, soil degradation, machinery costs, and education indices.