Perovskite compounds including sesquioxide materials have recently gained popularity in optical biosensing due to their high chemical stability and excellent semiconducting properties. These properties make perovskite materials an ideal platform for optical detection. In this line, this paper presents new real-time ultrasensitive plasmonic biosensor for large molecule detection based on metal/porous graphene/perovskite material (MPGP). The performance of the proposed device is reported in terms of the variety of perovskite media such as In2O3 and BaSnO3 materials and the nature of pores incorporated in the multilayer graphene which plays the role of amplifier medium. It is observed that the sensitivity of this device increases from 684nm/RIU using BaSnO3 to 948nm/RIU using sesquioxide In2O3. Whereas the quality factor reaches the maximum value Q = 74.5 for the porosity P = 7 % with BaSnO3 while Q = 9275 for (P = 28 %) with In2O3. However, the limit of detection is around 6 μM. Moreover, the proposed device exhibits an optical sensing region that can be adjusted by varying their electrical and geometrical parameters to meet the requirements of desired molecule detection.