Based on mode-coupled theory,the coupling characteristics of hole-assisted six-core fiber are researched systematically. The effect of nonadjacent fiber core on mutual coupled and self-coupled parameters is especially considered. And the influence on coupled parameter,crosstalk and mode area from the changing of fiber structure parameters is analyzed. Research results show that coupled effects among fiber core can be reduced effectively by making the best of fiber cross section through adjusting the structure parameters of fiber. Under the condition of keeping low crosstalk,larger single core effective area can be achieved.