In cryptography, hash functions have very important effects when it's used in the message integrity, digital time stamping, and digital signature. Hash functions compute hash value by a set of logical (primitive) operations that perform on a (32) bit words for authentication. Authentication process becomes very important especially manipulated message undetected that can have disastrous effects in Network Management and E-Commerce. In this paper, a proposal for new hash function based on MD5 is developed. The length of message digest is 224-bit through (4) rounds that each round has a pair of (16) steps. The final number of steps is (128) that make stronger function against collision attests and more secure than MD5.