Blue lines

HI, pls what are there blue lines for? How to remove them?

I’m guessing thats a downloaded model of sorts? The blue lines represent the connection between objects. It looks like you’re using version 2.4x so i’m not sure, but in 2.5, the blue lines show the presence of constraints. (See the constraint panel [and download 2.5])

that’s a constrain line,to remove if you are using 2.5x just un-check this option: in 3d view -> properties panel -> display tab -> relationship line.