To address the problem of changes of business processes for an enterprise or organization

we utilize the normal and exceptional instances to recommend the next possible activity for the current incomplete workflow instance.Since every workflow instance is a sequence of activity names

it cannot be calculated numerically.we firstly extract the order of each activity in the sequence as a number value

and then get a matrix which is similar to User-Item matrix in traditional recommendation systems.This matrix can facilitate the calculation of similarity between two workflow instances.Finally

we choose these complete instances which are most similar to the current incomplete instance

construct the activity list as the recommendation result by these instances.Experimental results show that the proposed algorithm is effective and efficient.