I was in 5th sem diploma, in mechanical tread. I am confuse for my next plan, but i want be a car designr, so what will i do ?

Then you have to go for engineering degree in mechanical

Better get specialized training on ProE, Catia and ANSYS. You may join CADD Centre in you city.

There is very less chance to be an car designer on basis of diploma in mechanical, without any exeperience. i would recommend you to pursue BE/BTECH and CATIA - AUTOCAD COURSES TOO. this will definately help you to be an car designer in future.

Either you can go for job directly after your diploma or you can do B_tech in mechanical or automobile engineering