The technologies and methods of real-time image fusion are introduced, and a novel design method of dual-waveband real-time IR image fusion system is proposed. In this system the FPGA chip ofVirtex-Ⅱ Pro is app lied to realize the main functions, including the kernel algorithm and the peripheral management, etc. Also it provides I2C as the host control interface. Compared with the traditional ones, this system is more compact, flexible and relible and has low power. The Lap lacian pyramid fusion algorithm being ported into this system is anatomized in the fields of comp lexity, real-time performance and resource occupancy factor in detail. Some methods to realize the key function units are also discussed, including the data synchronization of the two video channels, the frame buffer and the real-time transmission of data.