A novel dual period fiber grating sensor is demonstrated, which can measure strain and temperature simultaneously. The dual period fiber grating consists of a long period fiber grating (LPG) and a fiber Bragg grating (FBG) which is written in the same section of an uncovered hydrogen loaded fiber orderly. The Bragg wavelength of LPG and that of FBG have different sensitivity to strain and temperature, then strain and temperature can be determined simultaneously by measuring the two transmitted Bragg wavelengths of the dual period fiber grating. The accuracy of the sensory in measuring strain and temperature is estimated to be ±16 με in a range from 0 to 1700 με and ±0.8 ℃ from 20 ℃ to 120 ℃ respectively.