Large aperture photon sieve for imaging often has low efficiency and huge size of GDSII file, which makes their implementation difficult in practice. The composite photon sieve which compounds the zone plate to the R/3-2R/3 part of the conventional photon sieve is presented. The simulation result shows that the element can reach higher diffraction efficiency and significantly reduce the GDSII file size. In the experiment, a conventional photon sieve and a composite photon sieve with the same feature size are designed. The imaging result shows that the composite photon sieve can reduce the GDSII file size by 38% and has a better contrast than the conventional photon sieve. Therefore, the composite photon sieve is a good element applied in large aperture imaging in soft X-rays.