Well, without further information I can point you to a number of things.
If coffee: It is likely your decanter is off center during brewing. Additionally, if you own a glass decanter, it's possible that it is cracked and leaking. If this is the case, you may want to replace with a metal thermal decanter that is more resistant to that kind of damage.
If water, there are several things that could be going on. Your first step may be to visit the [[Mr. Coffee BVMC-SJX33GT Troubleshooting#Section_There_is_Water_Around_the_Base_of_Coffee_Maker|Troubleshooting]] page for this device as it has several causes for water around the base. Many users experience cracked water tubing in these types of coffee makers regardless of brand, so that is something you should definitely check.