Development of ecosystem helath index was based on the fact that up to now there is no single number that represents the quality of the ecosystem in Indonesia that was not consists of merely three parameters, i.e. water, air and land cover, but also should accomodate other components such as biodiversity index IKH), public health (IKM), as well as environmental health (IKL) since all of them are also important indicator for ecosystem health. Therefore, this research aimed to compile and to map health state of aquatic ecosystem, terrestrial ecosystem as well as built ecosystem in Indonesia for the last three years. Besides, the research aim was also to formulate a quantitative approach of ecosystem health assessment that could be a national guideline for environmental management in Indonesia. The last aim of the reseach was to develop a single number representing the ecosystem health by using a quantitative approach, covering aquatic ecosystem, terrestrial ecosystem and built environment. The research is designed to be carried out within three (3) years where the basic data will be extracted from documents of State of the Environmental Report (SoER or SLH) compiled by municipal, provincial and national levels in selected areas during the last three years. The data is also completed by direct field measurements in selected cathment areas in Java Island, covering the health status of aquatic, terrestrial and built environment. Laboratory analysis was conducted in Bogor Agricultural University and in Research Centre for Tropical Biology (SEAMEO BIOTROP), Bogor, Indonesia. The quantitative approach of ecosystem health assessment has been conducted by converting measurement result of six parameters of ecosystem (IPU, IPA, ITH, IKH, IKM and IKL) into an index, i.e. a single number without unit. Each of those parameters was weighed by similar weighing factor, ≅16.7%, so that the total of the weighing factor is 100%. Preliminary result obtained from the first year research campaign indiated that ecosystem health index of the selected areas is in between 62.1-72.3, where score of each municipality is as follows, 62.1 (Sleman Regency), 68.9 (Madiun Regency), 70.3 (Kulonprogo Regency), 72.3 (Malang and Bantul Regencies), whreas for urban areas is 71.6 (Malang Municipality), 75.0 (Yogyakarta Municipality), 75.1 (Bogor Municipality ) dan 75.1 (Malang Municipality). 1