The key to temporary plugging by ice crystals in coalbed methane wells is whether sufficient ice formation plugging strength can be achieved. Ice crystal formation and plugging capacity test equipment was designed to test the plugging capacity of ice crystals in a low temperature coal rock fracture. The experimental results show that the plugging strength is above 20 MPa. The tensile strength of saturated coal rock under freezing conditions was tested by the Brazil disk split method in order to study the mechanism of sealing strength of ice crystals. The results show that the tensile strength of frozen coal increases as the temperature falls beneath 0 degrees C. Both of these results proved that the technology of temporary plugging using ice crystals in coalbed methane wells is feasible and rational.