The invention discloses a chemical process of preparing 2'- desoxyadenosine, relating to a process for synthesizing organic compound. The process comprises following steps: (1) putting 6- chloride adenine and 1- acetyl base- 3, 5- bi (4-methyl phenacyl)- 2- deoxyribose and organic solvent containing phosphate phenolic ester compound catalyst into autoclave; carrying out condensation reaction under catalytic action to prepare 3', 5'- bi (4-methyl phenacyl)- 2'- deoxy- 6- chloride purine nucleosides; (2) putting compound and ammonia methanol into autoclave for aminolysis, the consumption amount of ammonia methanol is 4- 8 times of that of compound, the temperature is 10- 50 Deg. C, getting 2'- desoxyadenosine after aminolysis.