A perovskite LaMnO3 microinanostructure is a promising high-efficiency photocatalytic materials for the removal of various organic pollutants. This study presents the preparation of sub-micron LaMnO3 particles with polyvinyl pyrrolidone (PVP) as a structure directing agent to control the primary morphology and aggregations. Furthermore, the sample was annealed.at different temperatures to improve the crystallinity and perovskite phase formations. The possible formation mechanism was explained based on the annealing temperatures. An attempt has been made to study the effect of different morphologies of LaMnO3 particles for the degradation of RB dye under visible light irradiation. The removal efficiency of 95% for RB dye in 60 min evidences the superior degradation capability of highly porous LaMnO3 particles. The photocatalytic activity not only depends on porous structure, but also strongly based on crystallinity, and specific surface area of LaMnO3 particles. Hence, the porous morphology displays a superior photocatalytic activity than other LaMnO3 microstructures. (C0 2017 Elsevier Ltd. All rights reserved.