The effects of types and amounts of silane coupling agent on mechanical properties of vulcanized rubber microwave absorbing patch (VRMAP) were studied. The mechanisms of silane coupling agent’s effects on mechanical properties of rubber microwave absorbing patch (RMAP) and microwave absorbing patch’s ( MAP’s ) microstructure were also discussed by using SEM and FT-IR. The experimental resalts show that the tensile strength of RMAP could be increased through adding the filler of carbonyl iron powder (CIP) modified by silane coupling agent. RMAP filled with CIP, which was treated by silane coupling agent KH550, possessed a high tensile strength of 11.5 Mpa, which was 448% more than that of MAP whose filler was not modified by any coupling agent. It was found that the optimal amount of KH550 was 1.0 phr to 100.0 phr carbonyl iron powder. The effects of different modifying techniques on RMAP’s mechanical properties were also investigated. It is indicated that MAP whose filler is modified by the wet process has the highest tensile strength, but it is not the optimal modifying technique due to complicated wet process. On the contrary, the dry process was very simple, and VRMAP possessed fairly high mechanical properties, therefore, it was the perfect modifying process.