Based on the project of application and investigation of double-pole-composite strain tower of 1 000 kV ultra high voltage,the electrical test program of flexible jumper system in double-pole-composite strain tower is introduced.By the analysis of test result,it is shown that the electrical properties of the flexible jumper system can meet the engineering requirements. KEYWORDS：ultra high voltage；double-pole-composite strain tower；flexible jumper；electrical test；corona； radio interference