Abstract: Water injection of coal seam is a common way to increase gas extraction efficiency, research on the migration of gas of coal seam by injecting water can not only enrich gas seepage theory, but also can provide scientific basis for reasonably arranging water-flooding technology. In the paper, the research results on the gas migration in water injection coal seam were systematically sorted out and the applicability of the relevant theory was described in detail. The development direction of gas migration of water injection coal seam was pointed out: consider the nature of the water to study the adsorption and desorption law of coal; focus on the gas migration in the water-intrusion coal seam and environmental consequences; a more detailed study on the theory of multi-physical field coupling under the condition of water injection and gas nonlinear seepage is proposed.