Due to the defects of high aluminum residue and high oxygen residue, high titanium ferro alloy prepared by thermite reaction outside the furnace cannot be directly used in liquid steel refining process. In this paper, thermodynamics of the high titanium ferro with high aluminum used in liquid steel refining process was researched, and then effects of the amount and the aluminum content in high titanium ferro onthe liquid steel refining process were also studied. The results indicate that: using Ti and Al as composite deoxidizers, the deoxidizing product at 1873K is Ti2O3 when the aTi/aAl in liquid steel is above 8; but in fact, only when the aTi/aAl value in liquid steel is above 10, Ti2O3 precipitates as deoxidizing product. Using high titanium ferro with high aluminum content as deoxidizer, the content of aluminum and titanium in liquid steel can meet the requirements of composition for the related steel. With the increasing amount of high titanium ferro, inclusions in cast steel after refining transformed from silicate into Ti-Al-Mn composite inclusions；and at the same time, obvious or part of radial acicular ferrite forms around those inclusions, which refines the microstructure of steel. The aTi/aAl value in the actual system is 17.78(>8), which is consistent with the theoretical results. It is vital to control the values of aTi/aAl in the liquid steel when the oxygen content in liquid steel is high.