赢得摄影竞赛怎么说英语

To win a photography contest in English, you could say:
"I won the photography contest!"
or
"I took first place in the photography contest!"
You could also say:
"I was the winner of the photography contest."
or
"I emerged victorious in the photography contest."
If you want to be more specific, you could also mention the name of the contest, for example:
"I won the National Geographic Photography Contest."