Binary stars are common and it is necessary to model stellar populations using binary stars. We introduce a method to model binary-star stellar populations quickly. The method can also be used to model single-star stellar populations. The method is called rapid stellar population synthesis and it is based on a statistical isochrone database of both single- and bianry-star stellar populations. The database can be obtained easily from the CDS (or on request to the authors) and can be used conveniently for most stellar population studies and colour-magnitude fits. The main feature of using such a technique for modeling stellar populations is that it can save much computing time. Comparing to the method which evolves binary-stars using stellar evolution codes directly, the rapid stellar population synthesis method takes only one of 200,000 of the computing time. Although we can use the database to model stellar populations quickly, the involved uncertainties in spectra synthesis is small ($\sim$ 0.8%). I also introduce the method that uses the spectral energy distributions (SEDs) of single stellar populations to model the SEDs of composite populations.