Environmentally friendly fertilisers (EFFs) can improve the quality of cultivated land, purify the soil environment, and promote reduction in the amounts of fertiliser applied by improving efficiency. However, few studies have analysed the spillover effects of EFF applications on agricultural labour inputs. Hence, this study discusses the impact of EFFs on agricultural labour input, using the propensity score matching method based on the micro-survey data of peanut growers in the main producing areas in China. The results showed that EFFs have a labour-saving advantage, with a significant average reduction in the number of labourers’ input and labour days in agriculture production of 0.127 persons/mu and 0.601 days/mu at the 1% to 10% significance level. Additionally, EFFs improve yield and revenue but significantly raise production costs, ultimately increasing net revenue for farmers. The mechanism of the labour-saving effect is the capability of EFFs to reduce the amount and frequency of fertilisers applications, the amounts of pesticides applied, and irrigation water consumption by their technical characteristics and farmland’s ecological environment enhancement. Accordingly, the time effect strengthens the ecological regulation function and the application reduction effect of EFFs, further decreasing agricultural labour inputs. At the same time, the application of EFFs contributes to the adoption of mechanical deep tillage and fertilisation technology (MDTFT), thereby reducing fertiliser application and ultimately improving the labour-saving effect of EFFs. Heterogeneity analysis revealed that the labour-saving effect of EFFs is more obvious for farmers operating with a larger planting scale. To improve the labour-saving effect of EFFs, the findings imply that the application years of EFFs should be appropriately extended and the MDTFT should be promoted according to local conditions.