Mr.yavadee, yes, you can apply for the L type visa by yourself, the required documents:
i) Original passport which has more than 6 months left before it expires from the date of application for a visa and sufficient blank visa pages.
(ii) One completed Visa Application Form (e-Form / Download) with a recently-taken passport photo; all the items on the application form should be completed neatly with genuine information;
(iii) Proof of sufficient finances to cover all expenditures in China when requied.
(iv) Confirmed return flight ticket and its photocopy.

Mr.yavadee, you'd better contact the Chinese embassy in Tehran to enquire it whether you can apply for individual tourist visa or not. 2 years ago, Iranian tourists are advised to refer to local travel agencies to apply for Group Visa to travel to China.