This paper describes and analyses the impact of user mobility on the QoS of video streaming application in mobile IPv6 network. Mobile IPv6 testbed is built according to RFC 3775. QoS parameters such as throughput, delay, and jitter, are measured and compared. Two scenarios are considered. Those are when mobile node moves inside its own link and when it is in handover process. The measuring process is conducted during the delivery of video streaming application, by capturing packets of data flowing and traversing mobile IPv6 network testbed. Packet Ehering is performed to get the exact value of QoS parameters in UDP data gram packets. The result in each of the scenario is compared and analyzed to get the conclusion. The results show that the QoS of the mobile node that moves inside its own cell -regardless of its distance to the information source and how weakness the signal link is- is similar to QoS of the stationary node. The QoS of handover scenario is lower than the other scenario due connection reestablishment process between mobile node and correspondent node. We also fin that Qos of mobile node returning to its home cell is similar to QoS of mobile node moving inside its own link.