Abstract: In the liquid metal cooled fast breeder reactors （LMFBRs）,direct contacts between sodium and concrete is unavoidable.Due to sodium’s high chemical reactivity,sodium would react with concrete violently. Lots of hydrogen gas and heat would be released then.This would harm the integrality of the containment. This paper developed a program to simulate sodium-concrete reactions across-the-board.It could give the re- action zone temperature,pool temperature,penetration depth,penetration rate,hydrogen flux and reaction heat and so on.Concrete was considered to be composed of silica and water only in this paper.The variable, the quotient of sodium hydroxide,was introduced in the continuity equation to simulate the chemical reactions more realistically.The product of the net gas flux and boundary depth was ably transformed to that of pene- tration rate and boundary depth.The complex chemical kinetics equations was simplified under some hy- pothesises.All the technique applied above simplified the computer simulation consumedly,In other words, they made the computer simulation feasible. Theoretics models that applied in the program and the calculation procedure were expatiated in detail. Good agreements of an overall transient behavior were obtained in a series of sodium-concrete reaction ex- periment analysis.The comparison between the analytical and experimental results showed the program pre- sented in this paper was creditable and reasonable for simulating the sodium-concrete reactions.This pro- gram could be used for nuclear safety judgement.