In the development of a propellant tank using liquid oxygen and liquid hydrogen, the improvement of microcrack resistance of carbon/epoxy composites is necessary for the application of a composite material to tank structures. In this research, two types of carbon/epoxy composites with different matrix systems were tested to measure interlaminar shear strength (ILSS), one of the material properties to evaluate fiber-matrix interface adhesion indirectly. Short beam specimens were tested inside an environmental chamber at room temperature(RT) and at cryogenic temperature( - 150 °C) respectively. Results showed that the matrix system with large amount of bisphenol-A and CTBN modified rubber had good performance at cryogenic temperature.