Double electron beam interaction is studied by numerical simulation method. The simulation results show that when an electron beam (I) composed of many micro-pulses passes close to another electron beam (II) composed of many micro-pulses, the moving spatially periodic electric field of electron beam (II) can force the electrons in the electron beam (I) to follow a curve path, and electromagnetic radiation is stimulated by the acceleration of the electrons in the electron beam (I) along this curve path. In the same way, electromagnetic radiation is stimulated by the acceleration of the electrons in the electron beam (II) along this curve path. This novel electromagnetic radiation generated by double electron beam interaction effect is called double electron beam interaction radiation in this paper. Using a quasi optical resonator, coherent double electron beam interaction radiation with a high output peak power can be obtained.