Advance Encryption Algorithm is widely used cipher. Making the AES more secure is very crucial task in this network environment. We have proposed enhancement in AES by using two S- Box alternatively. We investigated different parameter in which we can focus to increase the security of AES. This algorithm focuses on avalanche effect of the algorithm in which increase its security against attack. This algorithm mainly focuses on byte substitution layer in which 2 S-boxes are used alternatively in consecutive rounds. The randomness of the S-Box is increase the avalanche effect and also increase the immunity power against attack.