Abstract: Eight beams of 351 nm laser entered the gold hohlraum through the laser entrance holes at Shenguang Ⅱ laser facility, and created X-rays to drive the DD capsule centered in the hohlraum to implode. The 9th beam of laser at 526.5 nm irradiated Pd backlighter foil, and generated a large area Pd L-shell X-ray backlighter to radiograph the implosion capsule. The radiographic image of the implosion capsule was recorded using an X-ray streak camera with a 20 ps time resolution. The X-ray backlighting radiography technique for the implosion capsule was established, and the imploding capsule was observed distinctly in the experiment. Experimental results of the trajectory and the implosion velocity of the capsule were presented, which can provide important information for the optimizati