In this project we discussed the maximum principle for elliptic equations staternseveral theorems, corollaries, and give a number of examples. Although the maximumrnprinciple for Laplace's and some other equations has been known for about a hundredrnyears, it is relatively recently that Hopf’s established strong maximum principles forrngeneral second-order elliptic equationsrnHence the proofs of weak and strong maximum principles of second order linearrnelliptic operator and other related corollaries are discussed in detail