The mechanical properties of in-service concrete bridges in the sea are subject to accelerated deterioration due to the harsh environment in which they are located, which poses a serious challenge to bridge transportation work. Therefore, it is necessary to analyse and study the mechanical property evolution of lightweight aggregate concrete in the marine environment and transport engineering design. In order to study the mechanical property degradation law of nano-modified ceramic concrete under the action of dry and wet cycles and temperature, tests were conducted on nano-modified ceramic concrete specimens at different temperatures (30 °C, 40 °C, 50 °C) and different numbers of dry and wet cycles (15, 45, 75), respectively. The test results showed that with the increase of the number of cycles, the change of compressive strength showed a typical three-phase law, while the split tensile strength showed the law of deterioration, strengthening, and then deterioration. With the increase of temperature, the compressive strength increases and then decreases, while the splitting tensile strength decreases continuously, and the decrease is greater. Under the combined effect of the two factors, three damage modes of compressive and split tensile were analysed. Finally, the uniaxial compression constitutive model and the formula for the attenuation change of mechanical properties of nano-modified ceramic concrete were fitted based on the test data under dry and wet cycles and temperature.