The temperature characteristics of triangular fiber Bragg gratings have been studied theoretically and experimentally. The results show that the rate of resonant wavelength with temperature of the triangular fiber Bragg gratings is the same as that of ordinary fiber Bragg gratings, and the spectral shape of the grating can be kept without being affected by temperature. For the characteristics, a novel strain sensing and demodulating system with temperature compensation is designed. In the system, the wavelength code of strain is converted into the signal intensity, and the ratio of the signal intensity and the referent light intensity is used as the measuring value of strain. Theoretical and experimental researches indicate that the strain is proportional to the measurement value, and the system has the temperature compensation property. At three different temperature conditions, the strain test results of the cantilever experiments show that the measurement error of strain is less than 6 micro-strain /℃. For adopting the ratio of the signal intensity and the referent light intensity as the measuring value of strain, it avoids the effect to the test results coming from the flatness and fluctuating of the broad band light source.