Aiming at these existing problems on decoding error in the XS detector,the causes of decoding error and its changing rules have been analy zed in this paper.These results show that MCP exiting electron cloud diame ter must cover about 1.64XS anode periods in order to obtain the best spatial resol ution. An XS anode with a period of 635μm has been designed and fabricated according to above-mentioned analytic results,and sampling of the anode output signal wavef orms is also finished.The maximum count rate of 1MHz and the spatial resolution of 4μm can be estimated in the light of XS anode output waveform linearity an d noise.