The invention discloses a reactor for organic synthesis, and relates to the field of organic reaction. The reactor comprises a bottle body, wherein a plurality of inserting openings are formed in the bottle body; a heating jacket is arranged outside the bottle body and comprises an outer jacket part and a heated part; the outer jacket part coats at least 2/3 area of the outside of the bottle body; the heated part is fixed at the bottom of the outer jacket part; the heated part is used for being in contact with a heat source and transferring heat to the outer jacket part; a heat conductor is arranged between the outer jacket part and the bottle body and the thickness of the heat conductor is 4-8mm; the thickness of the outer jacket part is sequentially increased from bottom to top; the thermal conductivity of the heating jacket is greater than 50W/M*K; and the thermal conductivity of the heat conductor is greater than 30W/M*K. The reactor disclosed by the invention is relatively small in cleaning difficulty and the experiment cost can be reduced.