With the rapid development of electronic communication technology, all kinds of electronic equipments have emerged in an endless stream, which generate a lot of unavoidable electromagnetic radiations while bring huge convenience to human life. These electromagnetic radiations not only affect the normal operation of electronic equipments, but also do harm to human health, and therefore it is particularly urgent to investigate the electromagnetic wave-absorbing materials. In this work, SnO₂@MWCNT wave absorbent was firstly fabricated via a hydrothermal process followed by heat treatment. Then SnO₂@MWCNT/silicone rubber wave-absorbing composites were obtained by solution casting method. XRD, Raman, TGA, XPS, and TEM analyses indicated the successful preparation of covalently bonded SnO₂@MWCNT absorbent with encapsulation structure. When the mass fraction of SnO₂@MWCNT was 7.5 wt% and the sample thickness was 2.6 mm, the SnO₂@MWCNT/silicone rubber wave-absorbing composite displayed the minimum reflection loss (RLmin) of -56.9 dB and effective absorption bandwidth (EAB) of 3.1 GHz. The outstanding wave-absorbing performances of SnO₂@MWCNT/silicone rubber wave-absorbing composites could be ascribed to the excellent impedance matching and dielectric loss capability. Furthermore, the corresponding 7.5 wt% SnO₂@MWCNT/silicone rubber wave-absorbing composite exhibited heat resistance index (T_HRI) of 196.3^oC, higher than that of neat silicone rubber (187.4^oC). Our fabricated SnO₂@MWCNT/silicone rubber wave-absorbing composites possess potential applications in the field of electromagnetic protection.随着电子通讯技术的不断发展，各类电子设备层出不穷，在给人类生活带来巨大便利的同时也产生大量的电磁辐射。这些电磁辐射不仅影响电子设备的正常运行，也会危害人类的健康。因此，电磁波吸收材料（吸波材料）的研究就显得尤为迫切。本文以硅橡胶为基体，以水热法和后热处理制备合成的SnO₂@MWCNT为吸波剂，经共混浇注制备SnO₂@MWCNT/硅橡胶吸波复合材料。XRD、Raman、TGA、XPS和 TEM分析表明已成功合成Sn-C共价键连接具备封装结构的SnO2@MWCNT吸波剂。当SnO₂@MWCNT用量为7.5 wt%且试样厚度为2.6 mm时，SnO₂@MWCNT/硅橡胶吸波复合材料具有最优的吸波性能，其最小反射损耗（RLmin）达到 -56.9 dB，对应的有效吸收带宽（EAB）达到3.1 GHz。优异的吸波性能主要归因于SnO2@MWCNT/硅橡胶吸波复合材料良好的阻抗匹配和介电损耗能力。此时SnO₂@MWCNT/硅橡胶吸波复合材料具有优异的热稳定性，其耐热指数（T_HRI）达到196.3^oC，高于纯硅橡胶的187.4^oC。因此，这种SnO₂@MWCNT/硅橡胶吸波复合材料在电磁防护领域具有广阔的应用前景。