Spinel oxide Mn-Co-Ni-O (MCNO) thin films were prepared by using a chemical solution deposition method (CSD). The electrical property and device performance based on MCNO thin films were investigated, including the responsivity (RV), noise spectra and the detectivity (D*). MCNO thin film with a thickness of 8μm was prepared and their sheet resistance versus temperature curves are measured. The optical immersed MCNO infrared detector based on Germanium lens was fabricated, and it possesses the advantages of relatively small time constant (～18ms), high responsivity (～4.4×103V/W) and high detectivity (～5×108cm·Hz0.5/W).