Quantitatively evaluating the ecological health of a small watershed is a basis of carrying out scientific planning of ecology and formulating scheme of practicable treatment.The small watershed of Lanlingxi was selected as an example and pressure-state-response model was used to systematically study the indicator composition of health assessment system,screening of indicators,determination of weight,processing of grid data,establishment of source database of evaluation indicator,determination of health evaluation model,and health grading based on Fishnet grid.Results showed that the model integrated twelve independent factors into health assessment of ecosystem.The methods could achieve combined application of statistic data and natural data of geographical element，and enhance the accuracy of health assessment of small watershed ecosystem and reflect the differentiation characteristics of health status of assessment units.It will provide theoretical and technical foundation for the health assessment of small watershed ecosystem.