Rules of evidence, along with their application, are of significant importance in IPRs litigation. It provides the crucial link between the determination of liability (as discussed in the previous chapter) and the measurement of damages (as to be analysed in the following chapter), embracing the functions of both civil substantive law and civil procedural law. From the perspective of the general, special and supplementary rules for distributing the burden of proof, this chapter discusses elements of liability and damages standards of IPRs infringements.