First notebook entry: Introducing myself

I am a graduated student, just began to foreign trade work, but my spoken English is very general,and I want to learn more to improve my oral English level

No one has noticed that you HAVE graduated. It happened in the past. 

I HAVE graduated. I just began to DO foreign trade work. ------However, I have no idea what foreign trade work is! So it may not be the right expression. Maybe you should say - "I have just begun to work in the foreign trade industry. "

BUT is okay - but HOWEVER would be better.

However, my spoken English is very general, and I want (or WISH) to improve my oral English level (ABILITY would be better here). 

Good luck with your English :)

First notebook entry: Introducing myself

I am a graduated student, just began to foreign trade work, but my spoken English is very general,and I want to learn more to improve my oral English level

I have graduated, and am no longer a student.  I have just begun working in the foreign trade field.  My spoken English is at a very general level, I would like to learn more to improve my overall level.

First notebook entry: Introducing myself

I have recently graduated from college, and I have just began to work in international trade. My English speaking ability is rather limited, but I want to become better.

First notebook entry: Introducing myself

I am a college graduate. I have started working in the foreign trade industry and I would like to improve my spoken English. I would like to speak at a more advanced level.

The above description is one of a few ways to write what you are trying to say.