I have a presentation about Luxembourg, it's ok if I say it in this form?? thanks!
Luxembourg, called "Grand Duchy of Luxembourg" is a small country of just 2,586 km and just over half a million habitants. their political system is a parliamentary monarchy, its capital is Luxembourg.
He is a member of the European Union, bordered by Germany, France and Belgium thus has no coastline
there three languages, German, French and Luxembourgish are spoken.
Luxembourg has a motto, it's meaning "want to remain what we are"
Luxembourg has a great cultural diversity because they were influenced by Europe Germanic and Europe Roman
any Luxembourg can express what becomes one of the most important cultural centers in Europe

Question

I have a presentation about Luxembourg, it's ok if I say it in this form?? thanks!
Luxembourg, called "Grand Duchy of Luxembourg" is a small country of just 2,586 km and just over half a million habitants. their political system is a parliamentary monarchy, its capital is Luxembourg. 
He is a member of the European Union, bordered by Germany, France and Belgium thus has no coastline 
there three languages, German, French and Luxembourgish are spoken. 
Luxembourg has a motto, it's  meaning "want to remain what we are" 
Luxembourg has a great cultural diversity because they were influenced by Europe  Germanic and Europe Roman 
any Luxembourg can express what becomes one of the most important cultural centers in Europe

Answer

1. You used too many different pronouns.
"their political system is a parliamentary monarchy"
"its capital is Luxembourg"
"he is a member of the European Union"
I suggest choosing either "it" or "they."

The second to last sentence should be: "Luxembourg has a great cultural diversity because they were influenced by Germanic and Roman cultures"

Answer

Luxembourg, called "the Grand Duchy of Luxembourg" is a small country of just 2,586 km2 (format the '2' into superscript) and just over half a million habitants. Their political system is a parliamentary monarchy, its capital is Luxembourg. 
It is a member of the European Union, bordered by Germany, France and Belgium thus has no coastline.
There are three languages: German, French and Luxembourgish.
Luxembourg has a motto meaning, "We want to remain what we are".
Luxembourg has a great cultural diversity because they were influenced by Germanic and Roman Europeans.
Luxembourg illustrates what has become one of the most important cultural centers in Europe.

Answer

Luxembourg, called "Grand Duchy of Luxembourg" is a small country of just 2,586 km with over half-a-million people/citizens. Their political system is a parliamentary monarchy, its capital is Luxembourg.
Luxembourg, (can't call it he, only it) is a member of the European Union and bordered by Germany, France and Belgium, therefore it has no coastline.
There are three languages spoken there; German, French and Luxembourgish .
Luxembourg has a motto, that means "we want to remain what we are"
Luxembourg has a great cultural diversity, because they are influenced by Europe Germanic and Europe Roman. Today, Luxembourg has become one of the most important cultural centers in Europe.