NOVELTY - 23-Hydroxy-20-piperidyl-5-O-mycaminoseyl-tylolactone (II) prepared using e.g. tylosin (I) and piperidine, and sulfonyl group-containing compound are esterified, to obtain 23-sulfonato-20-piperidyl-5-O-mycaminoseyl-tylolactone derivative (III). 23-Iodo-20-piperidinyl-5-O-mycaminoseyl-tylolactone compound (IV) prepared using compound (III), and organic solvent (d) are mixed, organic or inorganic base is added, piperidine is dripped, reacted, organic solvent is distilled off, water is added, pH is adjusted to 9-11, filtered, washed and dried, to obtain tildipirosin (V).    USE - Synthesis of tildipirosin (claimed).    ADVANTAGE - The method enables economical and simple synthesis of tildipirosin having purity of more than 98.2% with high productivity by safe and environmentally-friendly process in a short period of time without using devices in high temperature and high pressure. The conversion rate of each step of the reaction is up to more than 80%.    DETAILED DESCRIPTION - 0.04-0.1 Mol tylosin of formula (I) and 0.5-1 mol inorganic acid or organic acid are reacted at 60-95 degrees C for 0.5-1.5 hours under pH of 1-3, cooled, pH is adjusted to 9-11 using aqueous ammonia, extracted using organic solvent (a) 2-5 times, extracts are combined, 0.05-0.15 mol piperidine and 0.5-2 mol inorganic or organic acid are added, reacted at 40-90 degrees C for 1-4 hours, cooled to room temperature, water is added, pH is adjusted to 9-10 using aqueous sodium hydroxide, extracted using dichloromethane, organic phase is water-washed 1-3 times, dried using anhydrous sodium sulfate and distilled under reduced pressure, to obtain 0.036-0.081 mol 23-hydroxy-20-piperidyl-5-O-mycaminoseyl-tylolactone of formula (II). 0.036-0.081 Mol compound (II) and 0.05-0.2 mol sulfonyl group-containing compound are esterified at 20-40 degrees C for 1-5 hours in an organic solvent (b) under alkaline condition, reaction mixture is cooled, water is added, extracted with dichloromethane 1-3 times, dried using anhydrous sodium sulfate and distilled under reduced pressure, to obtain 0.034-0.066 mol 23-sulfonato-20-piperidyl-5-O-mycaminoseyl-tylolactone derivative of formula (III). 0.034-0.066 Mol compound (III) and 0.05-0.4 mol iodide reagent are reacted at 30-80 degrees C for 1-4 hours in organic solvent (c), cooled, water is added, extracted with dichloromethane 1-3 times, dried using anhydrous sodium sulfate and distilled under reduced pressure, to obtain 0.031-0.062 mol 23-iodo-20-piperidinyl-5-O-mycaminoseyl-tylolactone of formula (IV). 0.031-0.062 Mol compound (IV) and organic solvent (d) are mixed, 0.01-0.05 mol organic or inorganic base is added, 0.05-0.4 mol piperidine is dripped, reacted at 40-90 degrees C for 2-4 hours, organic solvent is distilled off under reduced pressure, water is added, pH is adjusted to 9-11 using aqueous sodium hydroxide solution, filtered, residue is washed and dried under reduced pressure, to obtain 0.025-0.058 mol tildipirosin of formula (V). The molar ratio of compound (III) and organic solvent (c) is 1:5-30. The molar ratio of compound (IV) and organic solvent (d) is 1:5-40. The mass ratio of residue and water is 1:5-20.