 This study investigated the technical potential of a high-pressure gas-liquid two-phase jet in increasing Colbert permeability and promoting Colbert methane extraction. It found that the non-uniformity of mixing and the expansibility of high-pressure gas-liquid two-phase jets between single and multiple streams make them show obvious pulse effects and considerably improve the rock-breaking performance. Moreover, it was determined that the shock pressure of a high pressure gas-liquid two-phase jet decreases with the increase in air pump pressure while its shock efficiency first increases and then decreases with the increase in air pump pressure. Additionally, the optimal air pump pressure differs for different water pump pressures. This article was authored by Long Yong Xu, Yongping Fan, Yunlong Yang, and others.