Is redirect 301 good for SEO ?

Hello,

I have site for games, like : http://www.site.com/games, i will move all content from folder (games ) to main folder /, then i will redirect by 301 from http://www.site.com/games to http://www.site.com/ , This process will drop down my site or Google will just replace link from http://www.site.com/games to http://www.site.com/ SAFETY ??

Note: i have built good backlink for main domain.

Thank you

i will suggest you, check this that's very helpful for you
premiumseosolutions.com.au/blog/2011/06/why-301-redirect-is-a-good-seo-strategy/

I have had good success with 301 redirects recently. I purchased a batch of aged domains and redirected them all to a money site and seen some good SERP movement for a low to medium difficulty keyword. Here's what I done:

1) Bought 20 aged expired domains with the requirements:

-previous content on the domain must be (loosely) related to my target money site
-must be at least 5 years old
-must have a solid link profile with a minimum of 100 links

I didn't really care about the page rank which helped reduce the costs of the purchase.

2) Posted 20 unique articles on the homepage (each article over 1000 words and related to my money site) and added images and videos.

3) Ran Scrapebox blast to index new content

4) Waited until the posts were indexed and let it sit for 2 weeks.

5) After 2 weeks, I added a 301 redirect to each site towards the homepage of my money site.

6) Saw increase in SERPs