To meet the special demands on the deflector of femtosecond streak tube camera, a kind of traveling-wave deflector for the high speed streak camera is designed. According to the design theory of traveling-wave deflector proposed by Finch, the design process is simplified and a deflector model is built by using the HFSS software. The high frequency characteristics and the pass bandwidth of the traveling-wave deflector are simulated and solved. The basic structural parameters are determined by matching the electromagnetic wave phase velocity with the electron beam velocity. Through the above method, a traveling-wave deflector is optimally designed for the high speed streak camera with the electron energy of 10 kV. The traveling-wave deflector is designed with the length of 44 mm, the plate spacing of 4 mm, the pass bandwidth of 4 GHz, and the deflection sensitivity of 119.8 mm/kV. The traveling-wave deflector is tested with the existing high-speed streak camera. The test results show that the design results are accurate and reliable, and the design method is proper. The work provides an effective way to design the traveling-wave deflector for the tube camera，and it can shorten the development cycle of high resolution scanning camera.