Coalition Formation is a key topic in Mult-iAgent System.The current strategies don't embody the difference of Agents.contribution to coalition for allocating utility averagely

so they cannot guarantee the coalition stability.This paper presents a novel behavior strategy for coalition formation.It remains the principle of non-reducing utility allocation

and improves the justice of allocation for accrued utility.In task oriented domains this strategies can achieve a global optimal solution

which is stable

speedy and distributed.