The invention discloses a microfluidic photoinduction polymer modification method. According to the microfluidic photoinduction polymer modification method, in a microreactor, photoinduction is adopted for grafting modifying of poly(vinylidene fluoride-co-chlorotrifluor ethylene) via free radical polymerization. Compared with the prior art, the microfluidic photoinduction polymer modification method possesses following advantages: microfluidic technology is capable of realizing accurate control and adjusting of reaction conditions, reducing catalyst using amount, and adjusting grafting amount; and the obtained modified polymer is high in application value in the field of microelectronics.