Abstract: In order to solve the calibration problem of the femtojoule laser energy meter, a special calibration system and method were proposed. The combination of fixed and variable two-stage attenuation mechanism was adopted in this system, which realized the calibration of laser energy meter with response wavelength of 1 064 nm, pulse width of 5 ns~1 μs and energy of femtojoule. The working principle, equipment composition and method of the calibration system were described. The key components and engine performance of the system were also described, and the corresponding test results were given: the uncertainty of energy repeat measurement was 3%, and the measurement uncertainty of the system could reach to 11%. Finally, the future improvement direction of the calibration system was proposed.