I found this explication //// BestShare: If your miner or pool computes a hash value that is lower than that maximum, then you or the pool have solved a block.
is that mean : if my share is less than my best share so i solved a block ?
You have to have a share that is more than the BTC Difficulty. Bestshare is the best share you have put up with your miner. If it's not more than the BTC difficulty well, it's just a share. Not a solved block.