arduino yun


previously my code for arduino uno+wifi shield work fine

Code and circuit the same

But when i switch to arduino yun,one part of the 2digit 7segment did not lighted?Does anyone know what caused this?

It's impossible to say without seeing your code and circuit schematic. Are we supposed to guess?

But there is one observation that can be made: you say it's the same code as you use on the Uno with a WiFi Shield -- the way that networking works on the Yun is completely different, and you WiFi Shield code will NOT work on the Yun.