This paper presents a novel approach to the design of a 4×4 slot array antenna operating at 5.8 GHz, utilizing a slot element based on the Koch Snowflake hexagonal fractal structure. The antenna is fed by a parallel feeding network, resulting in characteristics of high directivity. The proposed design was experimentally validated through fabrication and testing. Measurement results indicate a 5.7% impedance bandwidth (5.56~5.89 GHz) with well-matched impedance. At the operating frequency, the antenna exhibits commendable directional radiation characteristics and stable gain, achieving a peak gain of 19.85 dBi and a corresponding aperture efficiency of 80.69%. Moreover, the 3.dB gain bandwidth extends to 18.40% (5.13~6.20 GHz), demonstrating the efficacy of the Koch Snowflake fractal structure in enhancing the performance of slot array antennas.