CAN I GET TOURIST VISA FORM SAUDI ARABIA

The duration of stay per entry on a tourist visa is usually 30 days. If you want to stay longer in China, you can extend the visa within China. Each visa can be extended at most twice within China and each time allow another 30 days duration of stay. Or apply for a multiple-entry tourist visa, which usually has a duration of stay for 2 months. When it is going to the expire, you can travel to nearby regions or countries like Hong kong and Macau, then re-enter to get another 2 months duration of stay. It is possible for you to get a multi[le-entry Chian visa dince you have been to China many times. But I cannot guarantee.
If you want to obtain a visa with a duration of stay for 6 months, you can only apply for a business visa. One of the requirements is "Invitation Letter of Duly Authorized Unit" or "Confirmation Letter of Invitation".