Determination of the native state of a protein from its amino acid sequence is the goal of protein folding simulations, with potential applications in gene therapy and drug design. To predict a global minimum (GM) structure of a given sequence is a difficult task. A genetic algorithm (GA) is an efficient approach to find lowest-energy conformation for HP lattice model. We have introduced some new operators (symmetric and cornerchange operators) to speed up the searching process and give the result more biology significance. The result shows these new operators improved the success of prediction, compared with standard GA for benchmark HP sequence up to 50 residues