Abstract: A dual-grating cascade structure based on long period fiber grating (LPFG) cascaded with fiber Bragg grating (FBG) for temperature and concentration measurement has been proposed. The proposed fiber sensor was cascaded by LPFG micromachined by the femtosecond laser and FBG, and the transmission spectrum has two valleys, namely FBG valley at 1 551.9 nm and LPFG valley at 1 560.5 nm. The temperature and concentration sensing characteristics of the proposed sensor were measured at 30-50℃ and 3%-30%, respectively. The experimental results show that when the temperature rises, the FBG shows red shift with increasing wavelength, the sensitivity is 26.36 pm/℃, and the linearity is 0.950 8; on the contrast, the LPFG shows blue shift with decreasing wavelength, the sensitivity is -24.55 pm/℃, and the linearity is 0.914 2. When the temperature falls, the FBG shows blue shift with decreasing wavelength, the sensitivity is 25.00 pm/℃, and the linearity is 0.945 8; the LPFG shows red shift with increasing wavelength, the sensitivity is -21.82 pm/℃, and the linearity is 0.921 2. The FBG is not sensitive to the concentration variation. When the glucose concentration rises from 3% to 30%, the LPFG shows blue shift with decreasing wavelength, the sensitivity is 196.36 pm, and the linearity is 0.956 5. The proposed sensor has high sensitivity and good linearity for dual-parameter measurements.