Photothermal phase change microcapsules (n-OD@SiO2/PDA) were successfully prepared using n-octadecane (n-OD) as core material, silica (SiO2) and polydopamine (PDA) as composite wall materials. FESEM, FETEM, FTIR, DSC, TG, UV-Vis-NIR and simulated light source were used to characterize the surface morphology, chemical structure, thermal properties, optical absorption and photothermal properties of the microcapsules. The effect of different mass ratios of core material to silicon source (tetraethyl orthosilicate, TEOS) on the thermal storage performance of phase change microcapsules was investigated. The optimal mass ratio of n-OD to TEOS was 2:1. The results showed that the prepared photo thermal phase change microcapsules had regular surface morphology and obvious core-shell structure with good heat resistance, and the composite wall material could effectively protect the core material. Compared with the phase change microcapsules n-OD@SiO2, n-OD@SiO2/PDA had good heat storage performance with a melting enthalpy of 151.2 J/g, and exhibited excellent photothermal conversion performance with 91.8% of solar thermal conversion and storage efficiency.