Aiming at the allocation problem of collaboration design task, an allocation algorithm of design tasks based on negotiation mechanism is proposed in this paper. Firstly, it presents the task bidding process based on negotiation mechanism. Tenders and bidders will complete design tasks allocation according to the negotiation to avoid some problems because of forcible assignment, such as excessive allocation, low-enthusiasm members, and unreasonable process and so on. Secondly, it puts forward a decision algorithm of synthesis evaluation according to bidding information. This algorithm can realize the quantitative evaluation because of the consideration of competence degree, preference, workload and resource. The combination of negotiation and evaluation algorithm makes the allocation plan more reasonable, work efficiency higher and collaboration design project easier.