The invention discloses a method for catalytic synthesis of a conjugated gamma-
linolenic acid isomer by virtue of a surfactant-coated bacterium, wherein the method comprises the following steps (1) re-suspending each 
gram of 
lactobacillus casei CGMCC 1.574 bacterium in 5ml of a permeabilization treatment solution, treating at 37 DEG C for 20min, centrifuging and collecting a permeabilized bacterium; (2) washing the permeabilized bacterium with 60mM of a 
phosphate buffer solution which is at 5.8 in pH value; centrifuging and collecting the bacterium; re-suspending each 
gram of the wet bacterium in 20mL of the 60mM of 
phosphate buffer solution which is at 5.8 in pH value, dropping an 
acetone solution which contains 1% of dioleyl glutamate 
ribitol and uniformly mixing at the same time; 
processing at 4-40 DEG C for 2-6h, centrifuging and collecting the bacterium, and freeze-
drying so as to obtain a coated bacterium; (3) adding each 
gram of the freeze-dried coated bacterium to 500ml of normal 
hexane, uniformly stirring, adding 0.1-0.3% of gamma-
linolenic acid in terms of the 
volume percentage of the normal 
hexane and reacting at 4-40 DEG C for 1-12h; and (4) centrifuging and isolating the coated bacterium and recovering the normal 
hexane, so as to obtain a finished product, namely c6,c9,t11-conjugated gamma-
linolenic acid isomer. The method disclosed by the invention is short in reaction time; the coated bacterium can be recycled for several times, so that yield is significantly improved; and the method is free from environmental 
pollution and is capable of remarkably reducing production cost.