Metasurface, which refers to a two dimensional version of metamaterial, has received much attention since it can give huge impacts on electromagnetic waves with tiny thickness compared to the wavelength. Among various applications of metasurface, a metasurface microwave absorber, as a stealth functioning material, became more important due to the deepening competition in weapon system between superpowers. Although many studies were conducted for the microwave absorber, there is a difficulty in real application since most of them were designed without considerations on possible errors in fabrication process. Among a number of possible fabrication errors, this thesis focused on the sheet resistance deviation of the conductive ink which comprises the metasurface pattern. The optimized structure was obtained exploiting FDTD simulation and PSO algorithm. The responses of the attained absorber to the external electromagnetic field was investigated. In addition, the reason of the error tolerance was also investigated based on the extracted parameters by equivalent circuit model. The approach conducted in this thesis is expected to contribute to reveal the relations between fabrication parameters and absorber performances, and more effective design and real application of an absorbers.