The original pair-trawling and Japanese trawls, which have the disadvantages of long wings, short body, inflated cod-end, thin net twine, small mesh, etc., were tested in this scientific achievement in order to catch the bottom fishes that high off the bottom and fast-swimming (i.e.Larimichthys polyactis,Trichiurus lepturus) by enlarging net opening, reducing net resistance and increasing towing speed. Results showed that:

(1) It was conducive to increasing the vertical opening of net mouth, reducing net resistance ,increasing improve towing speed and expanding sweeping section area per unit time by optimizing net type, shortening wings length, enlarging mesh size of the net mouth and partial body, and increasing net mouth circumference. (2) The optimized gear can effectively increase the fishing yield, especially forTrichiurus lepturus. (3) The improvement of fishing gear also creats conditions for operation of net-hoist, which can shorten the time of net hauling and reduce labor intensity.