Check out these two guides:

60 seconds guide to getting your game to run in DOSBox
How to speed up DOSBox (by robertmo and mirekluza)

If you still have problems, post everything that you have tried for more help.

collector wrote:

Check out these two guides: […]
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Check out these two guides:

60 seconds guide to getting your game to run in DOSBox
How to speed up DOSBox (by robertmo and mirekluza)

If you still have problems, post everything that you have tried for more help.

I tried everything and it faster little bit but in te game i can set 14.2 frame per second (and i disable lot of function in graphic setting), i don't understand why, maybe my computer not strong enough?

What CPU do you have? What game? What have you changed in the conf file?

3D SVGA games can be *very* demanding on DOSBox - remember that everything has to be emulated in software. 14 fps sounds logical for a game like this on the hardware you have.
I suspect that the only way to get good performance would be lower resolution.

Here are some suggestions you can try by finding the following lines in the .conf file and edit them:

output=overlay (generally the fastest graphical output)
core=dynamic (some games can be really sensitve about this)
cycles=max (this will give you all cpu power available to you)
timed=false (this is only needed if you intend to play with an analog controller)