The signal to background (S/B) ratio is a key parameter to small angle neutron scattering (SANS) measurement. Higher S/B ratio is contributed to get a more accurate result. To improve the S/B ratio, the boron-lined honeycomb convertor neutron detectors (BHCND) array were designed in this paper, which refer to the 3 He detectors array design, based on the intrinsic detection efficiency angular sensitivity of single BHCND. The three-dimensional sensitivities of 3 He detectors and BHCNDs array were simulated and the S/B ratios were calculated and compared, respectively. The research indicates that the BHCND array could suppress background neutrons and improve the S/B ratio performing the advantages to replace the 3 He detector.