The invention discloses a carbon dioxide supplementary device of microalgae culture pond, which comprises the following parts: aerating groove area I, aerating groove area II, carbon dioxide aerating pipe, air aeration pipe, carbon dioxide supplying system, air supplying system and brack, wherein the aerating groove is next to the culture pond; the aerating groove area I connects the culture pond through channel as well as the aerating groove area II; one end of carbon dioxide aeration pipe connects the carbon dioxide supplying pipe; one end of air aeration pipe connects the air supplying pipe with a block of baffle in the aeration groove. The invention improves the carbon dioxide absorbance and utilizes the carbon dioxide effectively, which possesses obvious economical and environmental benefit. |