This chapter looks first to the legislative process that generates the export duties in China. The aim is to discover the common intention of decision-makers when designing export duties. The Five-Year Plan was subsequently identified as a trustworthy indicator to shed light on the priority of competing policy purposes. A textual analysis of the Guidelines of the Eleventh, Twelfth, and Thirteenth Five-Year Plans (which cover the period from 2006 to 2020) and relevant subsector plans reveals the policy rationales behind export duties at various points in time. Although China had prioritised the industrial purposes of export duties in the past, this role has been altered in the Guidelines of the Thirteenth Five-Year Plan (2016–2020), which makes clear that export duties together with other taxes on production or consumption could form part of a new ‘eco-tax system’. An analysis of the relevant subsector five-year plans and the development of China’s environmental policies (such as the resources and environmental protection taxes) shows further the increasing role of China’s export duties to curtail carbon leakage. The same chapter also explains why these plans can be a trustworthy indicator by discussing a series of observations on the drafting, enactment, and implementation stages of them.