Abstract: In the production of oilfields, the phenomena that oil or gas is stolen by boring holes on oil or gas pipe-lines often happen. If this delict cannot be held out, the oilfields will be disastrous and the environment will be polluted seriously. However, the current monitoring techniques for the pipelines can only detect and lo-cate the leaks after the pipeline has leaked. The guard against theft and real-time monitoring and alarming system for oil and gas pipelines based on sound wave detecting technique can detect the delict as a hole is being bored on the pipelines. So the theft of oil or gas by boring a hole on the pipeline can be avoided and eliminated. A good result has been obtained after this technique was applied.