With the characteristics of diversity, randomness, concurrency and decomposability, tasks in manufacturing field are very complicated, and so manufacturing grid(MG)should have considerable flexibility to deal with this problem. With the definition of node and arc, MG structure is converted into a small-world network. Given construction cost constraint, the problem of shortest task waiting time is transformed into the constrained optimization problem, and a corresponding flexibility analysis model based on average path length(APL)is proposed, and the premise of arc-length and node-distance are defined. The results of application example show that the analysis model is effective.