Based on the common biological phenomenon homogenous recombination,we set up a method of homogenous fragments recombination across whole genome (HFRG) which different DNA fragments from multi-parents are recombined across the global genome in a cell simultaneously for improvement of strains complex phenotypes mediated by many genes.We used classical strain-improvement methods to generate populations with subtle improvements in ethanol or temperature tolerance,and then recombined many different populationsA chromosome DNA fragments in a common Saccharomyces cerevisiae strain for improved its ethanol/temperature tolerance.