I want these forces are same direcitional
In this pink selection box you would want either 1) select an edge (or sketch entity) in the direction you wish the force to apply, or 2) select a plane normal to the direction you wish the force to apply. This should help you to set the direction of the force into a single direction rather than normal to the selected face.
thanks for your advices
I would probably Split the face rather than apply load across that entire face.
Can you attach your *.sldprt file here?
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