Under visible light irradiation, the plasmonic photocatalyst Ag@AgCl crystals were prepared from heart-like AgCl micro-crystals that were synthesized by a simple hydrothermal method firstly. The results indicated that the experimental conditions have a great effect on the morphology of Ag@AgCl crystals. The pure heart-like, and the mixture of heart-like and cubic shape Ag@AgCl crystals were synthesized by controlling the experimental conditions. Scanning electron microscopy, X-ray powder diffraction, and UV–vis spectra were used to characterize the obtained product. The photocatalytic properties of the obtained product were investigated by evaluating on photo-degradation of a model pollutant methyl orange (MO), indicating that the pure heart-like Ag@AgCl crystals exhibit enhanced visible light photocatalytic performance with 95.3% compared with mixed sample of heart-like and cubic ones (71.3%). The strong surface plasmon resonance (SPR) of Ag nanocrystallites can be responsible for the enhanced visible light photocatalytic performance of the as-prepared Ag@AgCl crystals.