The present invention relates to a method for secreting and producing a target protein into cell culture broth. More particularly, the invention relates to a microorganism co-transformed with a recombinant expression vector containing E. coli outer membrane protein F (OmpF) and a recombinant expression vector containing a target protein to be secreted into cell culture broth, as well as a method of secreting and producing the target protein into cell culture broth by culturing the microorganism. According to the invention, the target protein can be secreted into cell culture broth in a pure form without fusion with other proteins so that the efficient isolation and purification of the target protein is possible.