Abstract This paper inquired the reaction between Fe3+ and S2- in aqueous solution,and obtained some conclusions:The precipitation of Fe2S3 formed was considered to be kinetically controlled, While S and Fe2+ as the oxidation-reduction reaction products were thermodynamically controlled; Fe2S3 could react with Fe3+ to generate S and Fe2+, and Fe2S3 was unstable under acidic condition; Fe3+ tended to react with HS- under weak basic condition;[Fe(H2O)6-n(OH)n](3-n)+(n=1,2) was the main hydrolysis product of Fe3+ in aqueous solution, and its oxidability was very weak, so it was hard to oxidize H2S and HS-, but it was easy to react with S2- to generate Fe2S3 precipitation with small Ksp value.