In this paper Fibonacci series have been applied to Fiber Bragg Grating (FBG) and phase shift section to design a temperature and strain sensor in one fiber with dissociability effect. The reflection spectrum of proposed structure has two separate peaks. Variation of the measured temperature and strain affects the amplitude and central wavelength of these peaks. The amplitude and wavelength shift is measured according to the reference, which is the reflected spectrum of the sensor at room temperature and without applying external strain. By interpolation the functions of amplitude and wavelength shift of two peaks again the temperature and strain applied to sensor, the effect of temperature and strain could be separated. Transfer Matrix Method (TMM) has been used for calculating the reflection spectrum of structure.