[Objective]Study on carbon sink effects in Conversion of Farmland to Forest Project in Hongfenghu drainage basin in order to provide evidences for assessing carbon sink potential of conversion of farmland to forest in Guizhou Province.[Method]By investigating the implement of Conversion of Farmland to Forest Project in Hongfenghu drainage basin from 2000 to 2006,the carbon sink amount and effect of seven main tree species in the foreat region like Cunninghamia lanceolata,Cryptomeria fortunei,Amygdalus persica,Prunus salicina,Armeniaca vulgaris,Camptotheca acuminate and Catalpa bungei were calculated,based on which the amount of forest carbon sinks in Hongfenghu drainage basin in 2015 was estimated.[Result]Biomass storage and carbon sink amount in middle and young aged forests were increasing over time from 2000 to 2006,which reached 1.05×107 kg by 2006 and would engage more and more potential.Cunninghamia lanceolata has the superior carbon sink capacity in the seven tree species in the research region,of which the amount of carbon sink per unit area will be 106.51 t/hm2 by 2015,followed by Cryptomeria fortunei with the amount of carbon sink per unit area by 99.42 t/hm2.Armeniaca vulgaris has the weakest carbon sink capacity of all the seven species with the amount of 13.03 t/hm2.The total amount of carbon sink in seven tree species was 2.35×107 kg,while the average amount of carbon sink per unit area was 26.17 t/hm2,which could produced economic benefit of 7.17×106 yuan calculated on the price of 305.0 yuan/t or 5.91×106 yuan calculated on the price of 254.1 yuan/t.[Conclusion]Economic benefits of carbon sink effects of Conversion of Farmland to Forest Project in Hongfenghu drainage basin were great with huge appreciation potential.