Carboxylic acid preparing process

The present invention relates to a improved organic carboxylic acid preparing process, in which under the existence or Rh catalyst system, alcohol with n carbon atoms and CO are made to react to prepare organic carboxylic acid with n+1 carbon, atoms, especially the preparation of acetic acid through methanol oxonation in the catalysis of Rh catalyst system. It features that catalyst stabilizer isadded into reaction medium to avoid deposition of catalyst in the liquid phase. The catalyst stabilizer used in the present invention is one kind of pyridine derivative with substituent group (CH2)mCOOR and (CH2)mSO3R.