The mechanism of photosensitized decomposition of benzoyl peroxide by several anthracene derivatives has been studied. It comfirms that the photosensitized process is carried out by electron transfer.It is discovered that benzoyl peroxide can be decomposed by sensitizer of different anthracene derivatives which are used either electron donor or acceptor and the active radical which produces in this reaction can initiate the polymerization of MMA. It is considered that the BPO with positive charge in the charge transfer complex is easier to decompose into radical than that with negative charge

so the rate (Rp) of polymerzation of MMA in-itiated by the system of DCA/BPO has higher value than others.