After being concentrated, secondary mother liquor of VC was processed by way of esterification-conversion technology integrated with distillation in order to recover vitamin C(VC) and gulonic acid. The influences of some factors on the recuperation rate of secondary mother liquor were studies,which were the amount of sulfuric acid,the final concentration,the adding amount and the way of methanol,the amount of sodium carbonate. The results showed that the yield was higher than 70% and VC content in products could be up to 70%; the lowest gulonic acid concentration could be as low as 1%; the products contained less than 1% of methyl 2-keto-L-gulonate. This indicated that a new route could be opened up in dealing with secondary mother liquor of VC and this technology might be feasible and desirable.