Transfer from: http: //www.scrumcn.com/agile/scrum-knowledge-library/scrum.html#tab-id-17
When the product-do list entry or increment is described as "complete" when everyone must understand the "complete" what it means. Although this will be a huge difference between different Scrum team, but team members must complete work on what it means to have the same understanding, so as to ensure transparency. This is the Scrum team "completed" is defined to evaluate incremental product when completed.
This definition also be used to guide the development team to understand when Sprint Planning Meeting of how many products do list entry that they can choose. Sprint's goal is to deliver each Scrum team to follow the current "Finish" potentially shippable functionality defined increments.
Development teams deliver incremental product features in each Sprint. This increment is available, so the product owner can choose to publish it immediately. Each increment is appended before all incremental and fully tested, in order to ensure that all increments will work.
With the Scrum team matures, we expect the "Done" will expand the definition, include more stringent standards to ensure high quality.
Note that, if in each iteration, our criteria for being "done" too low, then this will lead to in each iteration, we will be left out of some of the work is completed, the work completed outside of the cumulative duration of the project will increase risk, and may lead to the person in charge decided to release the product when the product but because of excessive accumulation of work outside of completion can not be published, so that we also need an extra Sprint to make it stable.