Abstract: A TiC-NiCrBSi composite was deposited on the surface of carbon steel by CO₂ laser,and powder formula was adjusted to improve the appearance and microstructure uniformity of the cladding layer. Causation of gas porosity and cracks was analyzed and corresponding measures were taken to acquire integral cladding layer. The results show that good appearance of cladding layer can be obtained with the increase in TiC content to 40% while the appearance can be improved with the addition of molybdenum iron. Molybdenum iron can also be used to improve the uniformity of TiC distributed in microstructure. Cracks in cladding layer are cold cracks,adding TiC to NiCrBSi alloy can refine grain and thus inhibit cracking. But adding too much molybdenum iron will promote the sensitivity of cracking. Gas porosities in cladding layer are produced by the use of organic binder,and using low laser scan rate or inorganic binder can remove the gas porosity.