A biomedical stimulation protection device includes a current source, a first upper P-channel metal oxide semiconductor field effect transistor (PMOSFET), a first adaptive bias circuit, and six first stimulating metal oxide semiconductor field effect transistors (MOSFETs). The first adaptive bias circuit receives a power voltage (VDD), a double power voltage (2VDD), and a triple power voltage (3VDD). The first upper MOSFET and the first stimulating MOSFETs are electrically cascoded with each other. The first adaptive bias circuit turns on at least one of the first stimulating MOSFETs according to VDD, 2VDD, and 3VDD, so as to stimulate a physiological tissue and control a voltage difference between two terminals of each of the first upper MOSFET and the first stimulating MOSFETs to be lower than or equal to VDD.