Abstract: The toughness radiation of electron beam on compound target is a complex process. It is necessary to investigate the action of the electron beam and compound target under different conditions for optimizing the quality of X-ray production. Based on the theory of particle and material interaction, the design of structure for X-ray conversion target of accelerator was investigated by the Monte Carlo method’s Fluka software simulation. In accordance with the actual design parameters of the 9 MeV electron linear accelerator conversion target, the composite targets with different combination sequences of high and low atomic numbers were designed. The dosage field distribution, energy spectrum distribution and leakage electron of 9 MeV electron beam bombarding composite target were simulated and analyzed. Through the simulations of the combined target effect of the electron beam and different combination sequences, the relationships of different combination sequences and dose field distributions, energy spectrum distributions, angular distributions and leakage electron spectrometry were revealed, and the hardening effect of the energy spectrum is further analyzed. To confirm the reliability, parts of the relevant simulations were verified by experiments. The results show that the combined sequence of different targets in the compound target has some influences on the energy spectrum, electron energy leakage rate and angular distribution of photons, which is one of the factors to consider while designing composite targets.