Low creep high alumina castables enhanced by adding Si are developed by introducing sufficient amount of silicon, which is oxidized gradually at elevated temperature and convert to SiO2 in succession, which reacts then with Al2O3 to generate mullite, accompanying with some volume expansion, and consequently creep resistance of the castable gets enhanced. The new product can solve problems such as shrinkage, creep, cracks, lining subsidence and inclining in the case of normal high alumina castable subjecting to long-time high temperature and load, thus service life and safety of furnace linings are improved. Presently, the low creep high alumina castables enhanced by adding Si have been successfully applied in a number of domestic heating furnaces and magnesium reduction furnaces. They are well received by the users, with significantly improved service lives. This research result was approved by the Henan Science and Technology Department and won the Second Prize of Zhengzhou Science and Technology Progress.