Given the global environmental crisis caused by electronic waste (e-waste), the development of the advanced electronics using sustainable materials have attracted great interests, however, their preparation still remains a challenge. In this work, we proposed a fully degradable pressure sensor with cellular polylactic acid (PLA) with serrated wavy structure as electret layer and molybdenum (Mo) as electrodes. The developed pressure sensor shows a high sensitivity of 10 V/kPa and a prominent pressure resolution of 0.91%. This kind of biodegradable devices may pave a way for the development of novel sustainable electronics.