Cement-based materials are brittle and low in flexural strength, which can be greatly improved by adding organic monomers to cement-based matrices due to the polymerisation effect of added the organics. The solution polymerisation behaviour of organic monomer in cement paste and its effect on cement properties were studied. The organic monomers used can well polymerise themselves in cement pastes by the solution polymerisation effect under common conditions. As a result, the cement composites have a flexural strength between 17.8 and 33.4 MPa, greatly dependent on the amount of organic monomers added and it is stable when immersed in water, acid, alkali and salt solutions. The setting time of the composites can be controlled and regulated. 11 refs.