Based on irreversible four-temperature-level (FTL) cycle model of absorption heat transformer (AHT) plants with heat resistance, heat leakage and internal irreversibility, an exergy-based ecological criterion function of is proposed, which can attain a compromise in inter restricted relations between exergy output and exergy loss of AHT plants. When all losses are considered and different losses are ignored, detailed expressions and simplified expressions among ecological function, exergy output, exergy loss, and various loss factors are derived. Using illustrative calculations, the effects of various loss factors on the general characteristics and the optimal ecological characteristics are analyzed. The expressions and conclusions obtained herein are general, which can provide some new guidelines about parameter selection for practical AHT plants. (C) 2017 Elsevier Ltd. All rights reserved.