A new type fiber vibration sensor based on a tilted fiber Bragg grating (TFBG) interacting with a multimode fiber (MMF) is presented. The sensing head is formed by inserting a small section of MMF into a sing-mode fiber and the TFBG. The reflection light from this titled fiber Bragg grating includes two parts, the reflected Bragg mode and cladding modes. The cladding modes are coupled back into core mode as a function of the multimode fiber. The power of the cladding modes is sensitive to the vibration, so the external vibration measurement can be obtained through the average output power of cladding mode. The sensor device is simple due to the usage of the intensity demodulation method. The experimental results show that the root mean square (RMS) detection error of the average power is 0.01 μW within the temperature range from 20 ℃ to 70 ℃, so it is proved to be temperature independent.