Character lift off the ground gradually during a running animation

I have a marine model used in my start project, which will uncontrollably lift off the ground when running. I set up a animator controller that contains only a running animation. Here is about several seconds after playing:

Is this a problem of animation or something else? I did nothing except let it in a running state which have a running animation attached. Unity 4.3.4, using avatar.

And if it is a problem of animation, how do I fix this? By simply calibrating the character to origin is not preferred, because the animation do need a little shaking.


Could be a number of things. Have you unchecked “apply root motion” on the animator component of your gameobject?