A new kind of long slit soft x-ray streak camera is presented in this paper. The camera has a large working area of 0.1mm 30mm. Time distortion of the camera is minimized by improving the design of the electro-optical system of soft x-ray streak tube. The dynamic test shows that the camera has a temporal resolution of 5ps and a spatial resolution of 15Lp/mm along the slit length of 30mm at the fastest sweep speed of 2.5cm/ns. A new time distortion correction theory and its application is also presented.