Abstract: We extended the application range of the Pascal's law from incompressible fluid to soft biological tissue when investigated the mechanical principle of heart-lung interaction issues such as pulsus paradoxus. Furthermore, we originally found the Pascal's law could be extended even to incompressible solid inside the fluid. This extended Pascal's law may then have a general meaning. We temporarily name it the General Pascal's law. General Pascal's law states that pressure exerted anywhere in a confined incompressible fluid is transmitted undiminished throughout not only the fluid but also the incompressible solid inside the fluid. Pascal's law is only a special situation of General Pascal's law. This newly proposed General Pascal's law may be a possible basic hydrostatic law, disclosing the rule of the force transmission from liquid to solid, and may lead to a deeper understanding of the mechanical nature of the world and may lead us to rethink about some phenomena that we did not really know. In this paper the mathematical approach and experimental work of ours and other researchers' were included to support this new law.