A summary of several existing methods for measuring the speed of sound in the fluid in a pipe is presented first. Their basic principles, advantages and limitations are compared. Those methods are good enough for the fluid in rigid pipes, but not for the fluid in a compliant fluid pipe system. The paper proposes an accurate measuring method using a system for determining the transfer matrix parameters of fluid power components. This method can provide satisfying results for the fluid contained not only in a rigid pipe but also in other softer/deformable pipes, such as flexible rubber hoses.