In order to achieve accurate measurement of ambient temperature,a temperature sensor based on Michelson interferometer with seven-core fiber (SCF) is proposed. The sensor is fabricated by fusion spliced a taper in between a section of SCF and a single mode fiber (SMF).When light enters the SCF from the SMF,high-order modes of SCF in thin cone area will be excited for suddenly fiber diameter decreasing.After propagation in SCF,the high-order modes and the fundamental mode of fiber core are reflected by the end face of the SCF and continue transmitting in the SCF until reach the taper,these modes meet and interfere with each other,and then the accumulate interference is coupled to the SMF.The sensor samples with different SCF lengths are fabricated and experimentally investigated.The experimental results show that the temperature sensitivity of the sensor with length of 47 mm is 0.127 4 nm/℃ within the temperature range of 20—160 ℃,the fitting linear coefficient is 0.998 3,and the temperature resolution is 0.007 8 ℃.The measurement standard deviation of the sensor is 0.289 6 ℃ in the stability experiment.The temperature sensor has the advantages of easy fabrication,low cost,high sensitivity and large measurement range,which shows certain application potential in temperature monitoring fields.