Abstract: According to the mix calculation method of normal concrete and increasing the additional water of brick aggregate after 24h, the mix proportions of C20, C30 and C40 recycled concrete in different brick aggregate replacement ratio (0%, 30%, 50% and 100%) are calculated. With the increasing of the brick aggregate contents, the compressive strength of recycled concrete decreases. When the brick aggregate replacement ratio is equal to 50%, the workability and the compressive strength can achieve the optimal result. Based on the test data of 50% brick aggregate replacement ratio, the unified compressive strength calculation formula is proposed for the different strength grade recycled concrete at different age. The calculation basis is provided for the prediction of early compressive strength.