A comprehensive understanding of the reasons for over-fertilisation is critical to agro-environment sustainability, especially for the fast-growing farming areas under urbanisation. Previous studies are more quantitatively biased and in most cases, merely focus on demographical, economic and political factors whilst excluding in-depth qualitative and holistic investigation. To address this gap, this paper attempts to construct a conceptual framework to investigate the hidden mechanism of chemical fertiliser overuse through an empirical study in the Dancheng county of China. Such a framework is based on Kollmuss and Agyeman (2002), and Blake's (1999) works, but incorporates demographical factors and external barriers for explaining the awareness-behaviour gap. Results indicate that environmental awareness is not necessarily related with chemical fertiliser overuse as the reasons for farmers' inappropriate behaviours are embedded within an intricate network of economic, social-cultural and policy-influenced factors incorporating labour and time constraints, risk-averse decisions, intergenerational division, farm size, attachment to instant gratification, land attachment, peer pressure, distortion of agricultural and land use policies, which has roots in the agricultural marginalisation and urban-rural dichotomy. Based on the results, policy recommendations are provided.