Based on the panel data from China's 31 provincial-level regions in 1997-2016, this article measures the low-carbon efficiency with shadow price of agricultural pollutants. Due to the shortcomings of low-carbon efficiency evaluation of agricultural economic growth quality, its illusion can explain why the environmental quality has not improved, while the current low-carbon efficiency with expected and undesired output has been sorted. So, this article further discusses the existence of the agricultural low-carbon illusion in each provincial-level region, and analyzes factors of degree of the agricultural low-carbon efficiency illusion. The results show that, from 1997 to 2016, the average of agricultural low-carbon efficiency showed an overall trend of decreasing and then rising, it was higher in the eastern region than in the central and western regions. And the trend of "East-Middle-West" gradient decreasing was obvious, and the regional gap showed an expanding trend with obvious inter-provincial differences. In general, the number of provinces with agricultural low-carbon efficiency illusion increased first and then decreased with time. In the sub-region, the number of provinces with agricultural low-carbon illusion in the eastern and central regions gradually decreased, while that of the western region kept increasing, which meant the quality of agro-ecological environment in most eastern and central provinces really improved. The level of agricultural economic development and the agricultural production energy conservation technology, degree emphasis on agricultural development, structure of agricultural industry, scale of agricultural scale, agricultural disaster rate and human capital affect the degree of agricultural low-carbon efficiency illusion. The effects of the first four factors were found to be negative, while those of the others were positive. Based on the above conclusions, optimizing the allocation of agricultural resources, upgrading the level of agricultural production energy-saving technology and improving agricultural economic benefits are effective ways to promote the agricultural low-carbon efficiency and break the illusion of low-carbon efficiency in agriculture. Obviously, it is necessary to adopt advanced and applicable agricultural production techniques and management technologies continuously, provide timely agricultural meteorological and production information services, and improve the resource utilization efficiency and production and management skills of agricultural producers, so as to promote agricultural economic quality and reduce agricultural carbon emissions.