The invention relates to a low-temperature-resistant high-power coalmine-permitted water-gel explosive and a manufacturing method thereof. The explosive is composed of a methylamine nitrate solution, water, ammonium nitrate, sodium nitrate, formamide, urea, sodium dodecylbenzenesulfonate, sesbania powder, fine atomized aluminum powder, a composite alkali metal halide flame inhibitor, expanded perlite powder, a foam stabilizer and a crosslinking agent. According to the invention, sodium nitrate and sesbania powder are first well mixed; ammonium nitrate is dissolved in water, such that an ammonium nitrate solution is prepared; formamide is dissolved in the methylamine nitrate solution; the three are mixed in an agent mixing tank; the composite alkali metal halide flame inhibitor, the fine atomized aluminum powder, the expanded perlite powder, the foam stabilizer and the crosslinking agent are sequentially added; and the mixture is well mixed and is packaged into sticks. The explosive has high explosion power, and can be normally initiated and detonated under an experimental temperature of 0 DEG C to -20 DEG C. The explosive does not contain toxic component, and does not pollute the environment. The process is simple, and continuous production can be realized.