Considering the restriction of oceanic condition and water depth in offshore oilfield, and higher cost of drilling and data acquiring, the oilfield evaluation is constantly studied to maximize the case evaluation optimization and reduce the time of drilling, coring and testing jobs, and therefore speed up new oilfield evaluation economically and effectively. In this paper, based on example of marine-facies high-quality sandstone from NH-AB oilfield evaluation in Pearl River Mouth Basin of Miocene stratum, and based on feasible analysis of evaluation case optimization, and by means of evaluation optimization on well location and numbers, coring and testing,we successfully reduced two evaluation wells, and only one coring and testing needed, therefore saving about a hundred million RMB of exploration cost, and accelerating the evaluation jobs and reserve estimation. It can improve the work efficiency and economics of offshore oilfield evaluation, and provide a reference for quick evaluation of similar oilfield in Pearl River Mouth Basin.