I am getting married in 1 month I am thin according to me so I want to gain weight in 30 days so please help me out of this??

Yeah it is possible to gain weight in a month... problem is it won't be where you want it... and its likely to be concentrated into one area. YOu don't get to pick where it goes first... thats determined mostly by your genes. Some it's the gut... some it's the butt.

What are you trying to improve?

Arms? Legs? But? I'm assuming you want a bit of "definition" as the weight?

Its possible to gain one pound of muscle a week if you train and eat right, and if you are a beginer to weight training you should make some good gains fast as your body is not used to it so you would not have hit that darn wall yet.