This paper is devoted to introducing refinement into the theory of adjustment for reflecting prisms based on the fact that the characteristic matrix S_T,2φ of a reflecting prism could also be regarded as a transmission matrix in case the input to the prism is an angular vector. Thanks to this new conception, the two rules, related respectively to a small angular displacement ΔθP and a small linear displacement ΔgD of a reflecting prism have significantly been rewritten in terms of the definition of the rules and even the title of themselves. Thus, the theory of adjustment for reflecting prisms will come up to quite a high level in scientific and logical sense.