This paper focuses on how to obtain the optimal antenna location for circular layout distributed antenna systems (DAS) with selected maximal ratio combining (MRC) in the uplink. Considering the effects of path loss, shadow fading, Rayleigh fading and white Gaussian noise, we first derive the approximate cell averaged symbol error rate (CASER) in a circular cell at high signal-to-noise ratio (SNR). Then, we obtain the optimal antenna location by minimizing the approximate CASER. Simulation results validate the analytical results and show that DAS with optimized antenna location offers smaller CASER over the traditional co-located antenna system (CAS).