Under the assumption that there is technique uncertainty in R＆D，and the success probability of R＆D and market return is related to individual resource committed to them，we study how to use profit sharing arrangement to reduce moral hazard in cooperation of industry-university-institution and stimulate the university or institution to commit R＆D resource according to contract． Based on the comparative analysis of the incentive efficiency between fixed sharing arrangement，proportional sharing arrangement，mixed sharing arrangement， and improved mixed sharing arrangement，the optimal profit sharing arrangement for different condition is found out． Finally，a numerical example and a case study are given to illuminate the main conclusion of this paper．