NOVELTY - Synthesizing platinum-tin/carrier catalyst by microfluidic direct loading method, comprises (i) taking platinum and tin containing precursor, and carrier, dispersing in ethylene glycol, adding reducing agent, and ultrasonic mixing, (ii) taking two poly(methyl methacrylate) pressure bottles, labeling as S1 and S2, adding precursor solution into S1, connecting S1 and S2 by capillary tube, taking capillary tube channel as a reactor, and collecting product in S2 bottle, winding capillary channel on the aluminum heater to form a microfluidic reactor, and (iii) centrifuging, washing and drying.    USE - The method is useful for synthesizing platinum-tin/carrier catalyst by microfluidic direct loading method (claimed).    ADVANTAGE - The catalyst has good methanol and oxygen reduction catalytic activity, and meets requirements of proton exchange membrane fuel cell anode electrocatalyst.    DETAILED DESCRIPTION - Synthesizing platinum-tin/carrier catalyst by microfluidic direct loading method, comprises (i) taking platinum and tin containing precursor, and carrier, dispersing in ethylene glycol, adding a reducing agent, and ultrasonic mixing, where the molar ratio of platinum and tin is 1:1, (ii) taking two poly(methyl methacrylate) pressure bottles, labeling as S1 and S2, adding the precursor solution into the S1, connecting S1 and S2 by capillary tube, taking capillary tube channel as a reactor, and collecting product in S2 bottle, winding capillary channel on the aluminum heater to form a microfluidic reactor, and (iii) centrifuging the resulting product, washing and drying, where the capillary tube diameter is 100-250 mu m, the capillary tube heating section length is 30-120 cm, the capillary tube heating temperature T is 200-350 degrees C, the pressure used is fluid flow driving force, the gas pressure applied in the pressure bottle S1 is 2-5MPa, the gas pressure applied in the pressure bottle S2 is 1-4 MPa, the internal pressure in S1 is greater than S2 and the reaction temperature is 200-350 degrees C.