what is the flash gordon episode in the old tv series ?

Question

it has flash landing on a unknown planet and seeing doubles of himself and others .

Answer 1

Oh, the animated one, missed that. Probably Deadly Double, from season 2, 1980-1981. Here's an episode list for the animated series: http://www.pazsaz.com/fgordon1.html
They don't give summaries of the episodes, but you might find that somewhere else if you do a websearch.


Edited, this was wrong-
Maybe it was this one?
The Law of Velorum
Episode Number: 37 Season 1 First Aired: July 1, 1955
Flash goes looking for Dale, who has been abducted to take the place of her look-a-like Queen Lyra in a ceremony of death.

Or perhaps:
The Matter Duplicator
Episode Number: 29 Season 1 First Aired: May 6, 1955
After the invention of a matter duplicating machine, the galaxy's most valuable jewels are stolen, only to reappear mysteriously three months later.

Maybe you meant a different TV series, though. Go here, there's an episode guide for Flash Gordon: http://epguides.com/FlashGordon_1954/

Answer 2

I think this show was COMMANDO CODY. Hope this helps!!