Hi Mohabon,
you have used wrong parameters.
Take a look at :
http://www.agisoft.ru/tutorials/photoscan/08/The second Parameter (Max disctance (m) ,..dertmines the assumption for the maximum cariation of the ground-ELEVATION at a time. 1m is for your purpose too much. Try 0.5 or something like this.
The Third parameter ..Cell size with 100m is also too high.
In case the result of automatic dense cloud classification is not acceptable the procedure can be re-run using adjusted parameters (for example, if some on-ground objects like stones and small bushes were classified as ground points it is reasonable to reduce Max angle and Max distance parameter values).
Note: It is important to reset the assigned classes for the dense cloud prior to starting the procedure again with the new set of parameters.
Hope that is a useful information for you.
Best regards