The invention discloses a method for preparing carbon microtree by utilizing chemical vapor deposition. The method comprises the following steps: introducing a carbon source gas into a deposition chamber from the bottom of a vertical heating furnace and depositing and growing the carbon microtree in an 850-1000DEG C constant-temperature space by utilizing hydrogen as a carrier gas according to the ratio of the carbon source gas to hydrogen being 1:(3-8), wherein the deposition chamber is a cylindrical graphite piece, and a matrix is placed on the inner wall of a graphite cylinder; a device for adsorbing carbon black is hung at the center of the deposition chamber, the device for adsorbing carbon black is a graphite rod with the diameter which is 15-25% that of an effective constant-temperature zone, and the height which is 60-80% that of the effective constant-temperature zone, and the carbon microtree with the diameter of 50-200macrometers and the length of 0.5-1.5millimeters is prepared. A catalyst is not introduced, and thus the growing carbon microtree is high in purity, good in quality, and has good application prospects in the fields of medicals, biology and molecular electronics.