A novel multi-parameter sensor based on a cascaded long-period fiber grating with two different periods is proposed and demonstrated. The sensing properties of long-period fiber gratings with different periods are investigated in detail which indicate that the long-period fiber gratings with different periods and the resonant peak positions have obvious sensitivity differences to the same changes of the external parameters. Such properties are useful for the design of multi-parameter sensor. Through the control of the fabrication parameters and the period, the fabrication of the cascaded long-period fiber gratings is achieved with the CO2 laser. The temperature and refractive index sensing properties of the cascaded long-period fiber grating are explored through experiments. Multi-parameter sensing is realized with such cascaded long-period fiber gratings in the experiments.