The multi-purpose employment-programming model for 3-D parking lot is established in this study. After as of noninferior solutions are resolved by the constraint method from multi-objective programming. Then, group decision making with multi-criteria evaluation is further applied to find out the best compromise solution. The results not only can be used as the direction of decision-making, but also can be provided as the most flexibility of decision-making references. This study has employed the parking lot on the eastern coast of Keelung City as example for illustration. With surrey conducted among the residents as well as the introduction of some basic data of the site into the programming model, it is resolved that the total of 520 sq meter of space for commercial employment, 3,080 sq meter of space for community activity center, and 3,879 sq meter of space for hotel and restaurant will be the optimal utilization of such parking lot, in addition to the 28,050 sq meter of space that has been planned and is now under construction.