For requirement of accurate measurement of large-energy long pulse laser energy, the temperature characteristics of absorber for laser energy meter are numerically analyzed and researched. The results show that, the temperature of absorber inwall rises with periodic oscillation. As the wall deep increasing, the oscillation amplitude decreases rapidly. The temperature of absorber outerwall is without periodism, and it rises gradually with time. Meanwhile, the factors to affect the temperature rise are single pulse energy, pulse width and repetition frequency. When the single pulse energy is same, the shorter the pulse width, the higher the temperature rise of absorber inwall. And also the higher the pulse repetition frequency, the higher the temperature rise of absorber inwall. But when the total energy is same, the higher the repetition frequency, the lower the temperature rise of absorber inwall. By the optimization design of absorber structure, the total energy of long pulse laser sequence can be measured. As well as the energy of every pulse for low repetition frequency pulse sequence can be obtained, when the repetition frequency of long pulse laser sequence is less than 10 Hz. The work provides important references for the design and application of large-energy long pulse laser energy meter.