The　phenomena　of　variability　and　interference　in　the　natural　frequencies　of　weight-sensing　structures　applied　in　complex　working　conditions　must　solve　the　problem　of　reducing　or　eliminating　resonance　under　low-frequency　vibrations　to　maximize　stability,　accuracy　and　reliability.　The　influence　laws　of　the　additional　mass　with　relevant　characteristics　on　the　natural　frequencies,　which　include　the　components　of　mass,　stiffness　and　center-of-mass　distribution,　etc.　Firstly,　the　theoretical　formulas　of　the　mathematical　model　are　given　based　on　different　characteristics　of　the　weight-sensing　structure,　and　various　combinations　of　additional　masses　on　the　weight-sensing　structures　are　adjusted　in　the　X-,　Y-,　and　Z-directions.　The　key　factors　to　be　specifically　considered　in　the　theoretical　formulas　are　discussed　through　simulation　analysis　and　experimental　validation.　Secondly,　the　locking　strength　of　the　fastening　screws　of　some　components　was　changed,　and　another　component　was　placed　on　the　experimental　platform　in　the　experiment.　The　results　show　that　the　mass,　center-of-mass,　stiffness　distribution　and　other　factors　of　the　additional　mass　have　different　effects　on　the　natural　frequencies,　which　are　important　for　the　demand　for　high-precision,　high-stability　weighing　measurement.　The　results　of　this　research　can　provide　an　effective　scientific　evaluation　basis　for　the　reliable　prediction　of　natural　frequencies.　©　2023　by　the　authors.