TbFeCo is one of the most promising magnetooptical recording media because it shows a high uniaxial anisotropy and a fairly good Kerr effect, and its composition can be tailored to achieve a large room temperature coercivity. A basic study was carried out to determine the factors affecting the mechanisms of magnetization reversal and the regularity of domain growth at room temperature in TbFeCo films. A technique has been established to quantify the regularity of domain growth in terms of coercive squareness. It has been observed that intrinsic magnetization and uniaxial anisotropy are the two most significant parameters to affect coercive squareness. Deposition processes and conditions have a very slight influence on coercive squareness.