i have ip address below:
src-address is 192.168.1.168
dst-address is 192.168.1.189
i want to block access share file from src to dst address.
How can i configure it?
Pls help me.....

Please describe what do you mean by "access share file"?

try this, and post here your topology please.

i already try /ip firewall filter add chain=forward src-address=192.168.1.168 dst-address=192.168.1.186 action=drop
but still can't?
any solution for me?

Are you using a switch or a bridge? If you are that traffic will not pass through the firewall. It will stay in the switch or bridge. If using a bridge you can enable "Use IP Firewall" in bridge settings for your rule to work or use a bridge filter.

yes . correct i use the switch . how can i block it?

As cbrown said: You can't. Basic TCP/IP: hosts on the same network talk directly. They don't go through the router. If the traffic isn't going through the router you can't block the traffic on the router.

You'd need switches with layer 2 security features that let you do what you need to do.