Abstract: The yield-increasing effect of nano-carbon sol application on maize was assessed by using plant height, stem diameter and yield as evaluation indicators. The results showed that： the maize treated with different dosages of nano-carbon sol had higher yield compared to the maize without nano-carbon sol treatment; the highest yield（15 659.3 kg/hm^2） was obtained when the maize was treated with 150 L/hm^2 of nano-carbon sol, which was 2 591.3 kg/hm^2 higher than that of CK（13 068.0 kg/hm^2）, indicating that the yield was increased by 19.5%; the application of nano-carbon sol promoted the growth of maize, higher plant height and stem diameter were observed in the nano-carbon sol treated maize compared with CK, and the best growth was obtained when the maize was treated with 150 L/hm^2 of nano-carbon sol; the maize treated with different dosages of nano-carbon sol had higher ear length, grain number and 100 grain weight than CK, and the best performance in these indicators was observed when the application dosage of nano-carbon sol was 150 L/hm^2. In summary,the application of nano-carbon sol can promote growth and increase yield of maize,and the optimum application dosage was150 L/hm^2.