The invention discloses a recognition method for an underground single ancient channel under the condition of a dense well pattern. By adoption of an analogy method, field outcrop observation results are used for guiding recognition of the underground single ancient channel, and a model fitting geological thinking method is embodied. Through application of the recognition method in a Sulige gas field, quantitative description results are applied to three-dimensional geological modeling and serve as constraint conditions to enable the model consistency rate to be remarkably increased. According to the recognition method for the underground single ancient channel under the condition of the dense well pattern, aiming at morphological characteristics of the single ancient channel, dense well pattern drilling data are sufficiently utilized, tedious work of sedimentary micro-phase interpretation conducted on a single well is avoided, the phenomenon that the seismic datum longitudinal resolution ratio is not enough for determining is avoided, and the recognition method has the characteristic of being convenient to operate. According to application of the recognition method in the Sulige gas field, recognition accuracy of vertical sand bodies is improved to be less than 8 m from being 15-20 m, the original quantitative description results achieve quantification, the results are applied to three-dimensional geological modeling and serve as the constraint conditions to enable the model consistency rate to be increased by 10%, and the effect is obvious.