CCAST, World Lab, Beijing 100080, Peoples R China
; Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China
; SW Univ, Chongqing 400715, Peoples R China
; Chinese Acad Sci, Inst Theoret Phys, Beijing 100080, Peoples R China
; Ctr Theoret, Lanzhou 730000, Peoples R China
; Natl Lab Heavy Ion Accelerator Lanzhou, Ctr Theoret Nucl Phys, Lanzhou 730000, Peoples R China
Based on a chiral unitary approach (ChUA), S wave K pi scattering is studied. We consider K pi and K eta coupled channels on isospin bases. With only one parameter, the S wave K pi scattering phase shift data below 1.2GeV can be described, and the resultant S wave scattering lengths also coincide with the experimental values well. In this approach, a scalar resonance corresponding to the K can be generated dynamically. Its mass and width are about 725MeV and 594MeV, respectively. A resonance corresponding to the scalar K-0(*)(1430) can also be generated qualitatively.