i would like to increase my vocabularies,but i don't know what the best way to improve it,anyone can tell me what ppl learnt in native english speaking country?

make flashcards

write the word on one side and its definition on the other and try to memorize it and then have someone quiz you

When studying a foreign language I like to find readers which use new words and define them somewhere on the page you're reading. This beats having to turn to the back of a book and look up definitions from a vocabulary list.
Bilingual editions of stories are also good. You can refer to your own language's side of the book when you are stumped.
English has such a good written literature, with many genres, you should find something you enjoy reading.
Internet talk radio stations should also help you out. But I'm probably a bit naiveyou probably get English language TV where you are.