Aluminum metal is often used as thermocouple strips in infrared thermopiles because of its good Seebeck coefficient difference with polysilicon and low cost, the preparation of thermocouple strips is crucial in the preparation of MEMS process, and its structure and morphology have a great influence on the thermopile performance. In order to study the effect of different preparation methods on the morphology and performance of aluminum thermocouple strips, this experiment used metal etching process and stripping process to prepare thermocouple strips, adjusted sputtering power, photoresist thickness, exposure dose, ultrasonic power and other parameters to optimize the preparation process, and characterized the morphology by confocal microscope, SEM and step meter, and the resistance value by semiconductor analyzer. The experiments show that the high aspect ratio metal-aluminum thermocouple strips with width of 3 μm and thickness of 0.4 μm are prepared by ROL-7133 negative adhesive, pre-baking for 1 min30s, exposure dose of 85 mj/cm2, mid-baking for 1 min40s, and development for 48s by metal stripping process, and the overall morphology is good and the device resistance value meets the requirements.