The present invention provides a method for infrared imaging detection and positioning of an underground tubular facility in a plane terrain. Demodulation processing is performed on an original infrared image formed after stratum modulation is generated on the underground tubular facility according to an energy diffusion Gaussian model of the underground tubular facility, so as to obtain a target image of the underground tubular facility. The method comprises: obtaining an original infrared image g formed after stratum modulation is generated on an underground tubular facility; setting an initial value h0 of a Gaussian thermal diffusion function according to the original infrared image g; using the original infrared image g as an initial target image f0, and performing, according to the initial value h0 of the Gaussian thermal diffusion function, iteration solution of a thermal diffusion function hn and a target image fn by by using a single-frame image blind deconvolution method based on a Bayesian theory; and determining whether an iteration termination condition is met, and if the iteration termination condition is met, determining that the target image fn obtained by means of iteration solution this time is a final target image f; and if the iteration termination condition is not met, continuing the iteration calculation. By means of the method, the display of the infrared image of the original underground tubular facility is clearer, and the real structure of the underground tubular facility can also be inverted.