For how much time in a day i should put my baby is a walker?

If your intention to introduce baby walker is to let baby to learn to walk, I advise not to do so. This is because baby will learn how to walk themselves and no need any extra assistance for this major development. One day you will find your baby pull up himself by holding on something and start to explore how to walk himself. Any interference will detriment their ability to learn. If your intention is to place a baby in a safe place while you need to attend to other things e.g. housework, you can actually get a playpen/playard to confine your baby in a safe place for a while. For me, I choose to use exersaucer to entertain my baby for a while and make sure he/she is safe while I need to attend to other stuff. I will not let baby sit inside for more than 30minutes.

According to most websites, you shouldn't place your baby in a walker for more than 20 minutes a day. Personally I feel that as long as he's not in the walker for long periods of time, it's fine. A walker isn't where mummies should put their babies in for them to self entertain while she does her house work. That's not safe. It should be under supervision because baby would be mobile and bumping into everything in the house. You can read the article below for more about time limits in walkers: http://www.pediatricservices.com/parents/pc-21.htm

how old is your baby? i suggest to start out with 5 mins and not more then 20mins.

thanks