Strapped relativistic magnetron (strapped RM) was proposed and its PIC simulation study was carried out.By comparing the strapped RM with the traditional A6 model,we observe that the use of straps can significantly change the distribution of field in the interaction region and reduce the harmful effect of the intense RF field to the beam wave interaction.It can also lower the anode current and reduce the energy loss of the electron beam on the surface of the anode.All these help to increase the efficiency of RM.By PIC simulation,the efficiency of strapped RM can be more than 70%.It effectively get rid of low efficiency which is the first shortcoming of RM.