Abstract: In order to evaluate the efficiency of low carbon agriculture development supported by public finance in Heilongjiang Province, the author adopted DEA model, used the public financial support efficiency of low carbon agriculture as the object of study and 2008 to 2012 as the decision-making unit, and took the number of agricultural labor, fertilizers amount, total power of agricultural machinery, agricultural subsidies and technology spending as input indexes, while agricultural output and the carbon emission amount of agricultural machinery operation as output indexes. Meanwhile, the optimal scale and improving measures under each decision-making unit were found out by Deap 2.1. The results showed that the optimal efficiency of low carbon agriculture development supported by Heilongjiang’s public finance was in 2012, under the assurance of the expected level of agricultural output and the carbon emission of agricultural machinery operation, the input factors of agricultural subsidies were appropriate, the increase or decrease of inputs would not achieve the maximum output, but could affect the efficiency of financial fund. The results could offer references for the low-carbon agriculture development supported by public finance in Heilongjing Province.