In engineering practice, the optical fiber sensor with multi-parameter simultaneous measurement function has great market demand. For multi-parameter simultaneous measurement, a long-period fiber grating(LPFG) and a tapered fiber are cascaded to form a sensor. The sensing characteristics of the sensor for ambient temperature and axial strain are studied. Using the temperature and strain sensitivity of the two resonant peak wave-valley in the sensor transmission spectrum, the measurement matrix is constructed to eliminate cross sensitivity and complete the simultaneous measurement of temperature and axial strain. The experimental results show that the center wavelength of the resonant peak wave-valley of the sensor has a good linear relationship with temperature and axial strain. The maximum temperature sensitivity is 40.12 pm/℃ and the maximum strain sensitivity is -1.502 pm/με.