Based on the method of “emergency sealing of leakage channels by underwater melting of phase transition materials”, the fluidity test and uniaxial compression test were carried out for paraffin rosin and stearic acid rosin composites with different proportions, and the properties of the materials with different proportions were obtained. Then, the composite material with better performance was selected for plugging test in the soil groove model, and the plugging effect was analyzed. Test results show that with the increase of rosin content the kinematic viscosity of paraffin rosin composites increases exponentially while the kinematic viscosity of stearic acid rosin composite increases in cubic function. The addition of rosin changed brittleness into plasticity. The yield stress increases and the properties of the material change from strain softening to strain hardening with the increase of rosin content. Compared with pure paraffin, paraffin rosin composite material with 20% rosin has shorter sealing time, the combination with the surrounding soil is more compact and has better water plugging effect.