A cascaded fiber FabryPerot (FP) cavity fabricated by femtosecond laser with fiber Bragg grating (FBG) and its sensing characterization has been proposed and its temperature and strain sensing characterization has been studied. During two hours of stability test, the maximum FBG wavelength shift is 0.009 nm, and the maximum FBG power drift is 0.015 dB; the maximum FP cavity wavelength shift is 0.018 nm, and the maximum FP cavity power drift is 0.072 dB. When the strain is varying from 0 με to 450 με then back to 0 με, the FBG wavelength peak is shifting towards right then left with the wavelength shift 0.530 4 nm, and the strain sensitivity is 1.17 pm/με with linearity higher than 0.99; the FP cavity wavelength shift 0.4911nm, and the strain sensitivity is 1.10 pm/με with linearity higher than 0.90. When the temperature is varying from 50℃ to 200℃ then back to 50℃, the FBG wavelength peak is shifting towards right then left with the wavelength shift 1.418nm, and the temperature sensitivity is 10.09 pm/℃ with linearity higher than 0.95; the FP cavity wavelength shift 1.578 nm, and the strain sensitivity is 10.53 pm/℃ with linearity higher than 0.98. This paper provides not only effective method to solve the problem of single fiber for double parameter measurement, but also reference value for the measurement of multi parameters coupling and decoupling in complex environment.