In　view　of　the　low　rate　of　return　and　the　long　payback　period　on　the　parking　lot,　the　cost-benefit　analysis　of　the　underground　parking　lot　is　carried　out　to　determine　the　land　concession　policy　strategy　issued　in　Document　No.　193.　The　sensitivity　analysis　of　the　internal-rate-of-return　and　the　dynamic-payback-period　are　respectively　carried　out　from　the　charging　price,　utilization　rate,　commercial　facilities,　and　land　price.　The　results　show　that,　the　land　concession　discount　ratio　which　can　provide　reference　for　the　land　concession　price　of　the　underground　parking　lot　can　be　determined,　according　to　the　charging　price,　utilization　rate,　commercial　facilities,　and　land　price.