Abstract(1) How to determine the staple diagram in the stretch-breaking process, including the pseudo-stretch-breaking process has been analyzed and theoretical formulas of the staple diagram are shown.(2) When the breaking points of fibers truly stretch-broken concentrate in the position of the breaking accessory, the short fiber content of the staple diagram may possibly decreases or increases.(3) The short fiber content on Turbo Stapler increases frequently if the probability that one breaker bar pseudo-stretch-breaks the fibers by contacting the fiber bundle only once is more than about 0.06 (assuming the front roller and the breaker bar are about l 5cm apart).