What happens if a Person spent money on good things which are earned from bad ways Think That , a person is selling liquor or weapons , Now he has done the business some time and now he is a very rich person .

According to Buddhism Selling liquor and weapons are bad businesses . 

Now he is spending money for good things ;) 

Ex:- doing lots of charity work .

So now what will happen .

If he did more good things more  no harm will come for him ? 

Can you explain me this :) Thanks in advance.
There is no problem at all. It will have mixed result (if casue is really mixed) or each action will have it's own result (selling liquor - bad, generosity - good). Amount of the result is not just lineraly depend on the amount of action, it's also depend on the level of development of mind of the performer. There is more factors to play in the ripening of karma.