Abstract: A two-dimensional multi-point-reflection long-optical-path gas sensor probe includes: a protecting housing and a multi-point total reflection type long-optical-path module arranged in the protecting housing. The multi-point total reflection type long-optical-path module includes two right-angle reflecting prisms or mirror pairs spaced at a set distance, and inclined surfaces of the right-angle reflecting prisms or mirror pairs are oppositely arranged and parallel to each other. A set deviation exists between center lines of the two right-angle reflecting prisms or mirror pairs, and the deviation can enable light beams parallel to the center lines to be reflected for a set number of times between the two right-angle reflecting prism or mirror pairs, so as to form a two-dimensional parallel light beam group. Thereby increasing a measurement optical path of gas absorption, which is beneficial to improve the detection signal-to-noise ratio and the measurement accuracy.