Abstract: Signal-to-noise ratio (SNR) is a key parameter to evaluate the detection performance for a remote sensing system. A mathematical model to estimate the SNR uncertainty for aviation multi-angular polarimetric radiometer (AMPR) is proposed through analyzing the working principle of AMPR and discussing the SNRs of measured Stokes vectors and degree of polarization. Based on the proposed model, the AMPR SNR uncertainty has been validated in laboratory by using integrating sphere source. The experiment results indicate that the SNR uncertainty of AMPR is no more than 10% or 5% (1σ) for the degree of polarization less than 1% or 2%, respectively.