Although the permanent seeking to amend legislation related to the government construction contract, achievement of the public interest thought challenges activation of these amendments. This study handles one of the most important problems faces government construction contract: "the mechanism to keep bid priority" . This problem arises from the contrast between the bid evaluation principles and the final priorities principles, when the final certificate of payment is calculated. The variance appears in the following issues: 1) difference between tender quantities and final executed quantities; 2) applying the points system for bid subjective variables evaluation without using the same principle at final priorities; 3) considering the modified rates formula, to adjust monthly payments, when calculating the priorities not for tendering choosing principles. This study did not address improving the mechanism to evaluate bids, but focused on legislative frameworks for procedures of contractor who must retain its priority for all the contract duration without prejudice to the principle of balanced contract.