I've linked two tables, but found that there were only 3 types of links, However, what I what to do is to include all the records from both tables, how can I do that?

It sounds like you want to combine records from two tables (so if one contains records APPLE, ORANGE, PLUM, and the other contains records LETTUCE and ONION you want a single recordset containing APPLE, LETTUCE, ONION, ORANGE, and PLUM.
What you need is a "union query".

1) Make a query which selects the field(s) you want from the first table.
2) With the query open in design view, select SQL from the view menu.
3) If your table is called tblFruits the query's SQL will look something like this:

SELECT tblFruits.*
FROM tblFruits
ORDER BY tblFruits.Name;

4) To include another table called tblVegetables, change the code as follows:

SELECT tblFruits.*
FROM tblFruits

UNION SELECT tblVegetables.*
FROM tblVegetables
ORDER BY tblFruits.Name;

5) There's other customisation you can do - see the help file.

very helpful. thanks a lot :D

Can we make a new query out of this "union query"? if so, how to do it?
many many thanks!

If you're using VBE it works the same as any other query, if you're using the Query Designer simply change the view to SQL View and enter the code as shown above.