Energy design technology is one of the key techniques of Fourier telescope. Laser propagation in the atmosphere and its impact on the energy of the laser beams are analyzed. According to the uplink and downlink transmission of energy, a total laser energy calculation method of Fourier telescope system is derived, and the corresponding applicable conditions are given. Meanwhile, based on radiation theory, a fast energy estimation method is proposed by which the required total transmitter energy of a Fourier telescope for 1000 km low-orbit objects is estimated. The effects of transmitter energy imbalance on the image quality are pointed out and simulated. It can be concluded that the intensity differences among laser beams of transmitter array must be less than 5%. From the atmospheric transmittance, laser emitting aperture, beam collimation, transmitting scheme, speckle effect, receiving technologies, image reconstruction techniques and other aspects, the design ideas and measurements to reduce energy loss are put forward.