A two-photon excited fluorescence lifetime microscopic imaging system based on a newly-developed high repetition rate picosecond streak camera is presented. The high repetition rate picosecond streak camera is the emphasis for introduction. In order to increase the measurable sweeping range and maintain high temporal resolution as well, and in order to realize high temporally resolved sampling measurement in two dimensions to improve sampling speed and exploit effectively the advantages of the streak camera, authors specially designed and developed a streak image tube with large area and high temporal resolution and a ramp voltage streak circuit with repetition rate up to 1 MHz. The streak camera based on the key components above mentioned is characterized with high repetition rate, tunable sweep rate, high temporal resolution, large effective area of work, low nonlinearity and small triggering jitter. A Ti:sapphire laser provides mode-locked, ultrafast femtosecond pulses with a fundamental frequency of 76 MHz which is reduced to 1 MHz with a pulse picker. The temporal resolution, sweep rate and nonlinearity are calibrated with a tunable delay generator and etalons. Temporal resolution of the system is 6.5 ps, nonlinearity is 2.60%, and the measurable time range is from ten picoseconds to tens of nanoseconds. Streak images of Rhodamine 6G and Coumarin 314 are obtained and the results agree well with those reported in the literatures.