Environmental Management System (EMS) has recently been advocated for most economic sectors. Construction, one of the pollution generators creating destruction to the environment, is by no means exempted from EMS. However, in implementing EMS, the greatest obstacle found is the lack of objective performance evaluation criteria. To overcome this, Environmental Performance Assessment (EPA) is introduced to assess environmental performance, which however is not popularly adopted in the construction industry. This paper attempts to develop a series of input (EOIs) and output (EPIs) indicators for EPA and measure their relations by using robust fitting and spectral methods based on survey and interview results undertaken in Hong Kong and Australia. The results show that the proposed EOIs correlate strongly with EPIs. Therefore, EPA can help improving and predicting environmental performance of an organization