This paper investigates a new type of concrete blocks which integrates a form-stable PEG/SiO2 composite PCM with the melting temperature of 28 °C and the latent heat of 113.6 kJ kg-1. A comprehensive analysis on the characteristics of sample concrete bricks shows that the properties of PCM concrete bricks are significantly influenced by the quantity of the PEG/SiO2 composite PCM. When the addition of composite is ranging from 0 to 18%, the apparent density, compression strength and thermal conductivity drop from 2.20 to 1.87 g cm-3, 23.6 to 0.69 MPa and 0.94 to 0.59 W m-1 K-1, correspondingly. The optimum amount of PCM in the concrete blocks was determined as 7.5%. The thermal performance of the PEG/SiO2 composite PCM concrete was also evaluated by comparing the temperature variation of a test chamber with PCM concrete and a test chamber without PCM concrete significantly. The results show that the PCM concrete can narrow the indoor temperature swing, which may help to improve the indoor thermal comfort in passive solar chambers.