Rayleigh scattering method can be used to investigate the cluster size and the cluster formation process, and its advantages are that it is easy to perform and non-disruptive. In this paper, by measuring the Rayleigh scattering intensities of clusters generated respectively in pure xenon gas and hydrogen-xenon gas mixture, the relationships of Rayleigh scattering intensity to time, backing pressure, and mixture ratio are studied, and according to these relationships, the average sizes of clusters under different conditions are estimated. Through the scaling law of the Rayleigh scattering intensity obtained in hydrogen-xenon gas mixture with respect to upstream gas pressure, i.e., I= (1.5 10-5)P6.47, the hydrogen of mixed gas is found to be conducible to the generating of xenon clusters. The advantages of hydrogen-xenon gas mixture for generating clusters are analyzed theoretically from the perspective of thermodynamics and intermolecular forces, and a new phenomenon, i.e., the hydrogen xenon gas mixture is not easy to liquefy, is found. This finding provides a new way to generate larger size clusters. Our results are expected to provide guidelines for the future experimental researches of the X-ray generated by xenon clusters and of the neutron generated by the deuterium-xenon mixture gas.