While it is technically possible, it is not recommended. Installing artificial grass directly over an existing lawn can lead to a variety of issues. The old grass may eventually decompose, causing uneven surfaces and drainage problems. Weeds or other vegetation might grow through the artificial grass, disrupting its appearance and structure. It’s best to properly prepare the area by removing the existing grass, compacting the soil, and adding a suitable base material before installing the artificial grass. This approach ensures a level, stable, and long-lasting foundation that allows the artificial grass to perform optimally and maintain its appearance over time.

Original Source: https://www.quora.com/Can-I-install-artificial-grass-on-top-of-my-existing-lawn/answer/James-Rider-15