Abstract: The invention permits to realize production of sugar syrup of refined purity simultaneously with harvesting. The invention is in creating new technological process, which includes thermal and acidic treatment of sugar-containing juice, electrochemical treatment, ultrafiltration, electrodialysis, ion-exchange and sorbent treatment, juice concentration by reverse osmosis and completing evaporating which ensures long-term storing. The technological rules of juice treating secure a trustworthy operating lifetime of ultrafiltrative, reverse osmosis and ion exchange membranes for the period of processing the crop. The sugar-containing product, obtained from the usage of the invention can be used in confectionery, bakery, canning industry, beer and non-alcohol production.