A new Al-LiTaO3-ITO infrared detecting structure on quartz glass substrate with a micro bridge is designed. Under the response/reference dual-element configuration, undesirable signals, caused by vibration, ambient temperature change and sunlight, are cancelled out at the input of the preamplifier circuit. The LiTaO3 thin film was chosen as infrared sensing film and prepared by a sol-gel process using lithium acetate and tantalum ethoxide as starting materials. The fabrication process of device is discussed in details. The dielectric properties of the sol-gel prepared LiTaO3 thin film were measured using evaporated Al dots as front electrode and the ITO substrate as bottom electrode. The dielectric coefficient of LiTaO3 thin film is about 53.28 at 1kHz. The dielectric coefficient and the dielectric loss appear falling tendency within the measured frequency range from 40 Hz to 10K Hz. Voltage response experimental results of the LiTaO3 device is obtained by an infrared device measurement system and indicate that the response voltage peak is about 9685V/W at 75Hz, and the specific detectivity D* peak of the device is near 6.12×108cmHz1/2W-1 from 70Hz to100Hz.