Measurement of fluorescence lifetime plays an important role in fluorescence lifetime imaging technology. If the Time correlated single photon counting method is used to process the signal of fluorescence lifetime images, it can make the real time imaging which have the virtue of high timing resolve and high signal to noise ratio. Multi-wavelength channels are used to record the lifetime simultaneously in four-dimension TCSPC system design. Four-dimension TCSPC imaging can be used to record the photon density over time, wavelength and coordinates of the scanning area. Analysis shows that the counting efficiency and the amount of information in the data can be increased by recording the fluorescence in several wavelength channels simultaneously. Multi-wavelength imaging was also successfully used to separate different fluorephores in stead-state images.