A method for desalting a salt-containing L-
carnitine solution comprises the following steps: selecting the salt-containing L-
carnitine solution with a weight concentration of 6.1% 2000 Kg, adjusting the pH value to 5 to 10, separating impurities, pre-desalting by an
electrodialysis method to achieve the
desalination rate of 60 to 90%, separating inorganic
ammonium salt to obtain the pre-desalted salt-containing L-
carnitine solution, desalting the pre-desalted salt-containing L-carnitine solution by resin exchange method to obtain a salt-containing L-carnitine solution, evaporating, concentrating, removing
ammonia, and crystallizing to obtain 113 Kg L-carnitine product with a content of 99.74%, wherein the yield of L-carnitine is 92.6%. By adopting
electrodialysis and resin exchange for desalting the salt-containing L-carnitine solution, the method can greatly reduce the use amount of resin and achieve less equipment investment, lower consumption of auxiliary materials, lower
energy consumption, less amount of
wastewater, higher yield, higher quality of the L-carnitine product, and greatly reduced
desalination cost of the salt-containing L-carnitine solution. Additionally, useful inorganic
ammonium byproducts can be obtained.