1 more question for 301 URL

I have 2 sites in the same niche which have good ranks of a keyword. The first site is #5 of Google, the other site is #20 of Google. I want to 301 the second site to the first one, is it benifit or cause penalize?

Whats the goal?

Meaning are you trying to forward it for actually forwarding traffic or "SEO" benefit?

Does the number 20 site get traffic?

If it were me I would put a link on the home page of the #20 site to the #5 site, that way you get link value passed and still have the chance to rank the #20 site higher. Thus taking up double the SERP real estate and also getting the traffic from both sites. Aka helping the number 5 site rank better and still getting traffic from both, means more money for you in the end.

(assuming your making money from the site)

I made a big "assumption" there that your making money off the site. But you could have any one of thousands of goals here, and you gave very limited info, so its hard to accurately direct you.

sell the second site