The CiADS (China initiative Accelerator Driven System) project plans to build a 250-kW experimental target before construction of the 2.5-MW spallation target. In this paper, the effect of proton beam distribution on the performance of the 250-kW target is studied. Hence, a hollow beam distribution, formed by a Gaussian beam scanning around the center of the beam window, is proposed. Then, combined with the orthogonal test method and the CRITIC (Criteria Importance through Intercriteria Correlation) method, four key geometric parameters of the target flow channel are analyzed to simultaneously achieve optimization of the target performance from the viewpoints of both the maximum temperature and velocity under steady-state condition. Finally, transient analysis of the initiation of the Gaussian beam scanning is conducted; the calculation time was 15s. The results show that the temperature on the window rose gradually until reaching its maximum value corresponding to the steady-state analysis. Detailed analyses showed that the optimized target design is capable of meeting the thermal-hydraulic and mechanical requirements.