The optical properties of quantum dots have a close relationship with the size fluctuation，density，strain filed distribution of the dots and the spacer layer thickness. InAs/GaAs quantum dot with GaNXAs1-X strain compensation layers （SCL） is theoretically investigated for improving the crystal quality. The reduction effects of the spacer thickness are discussed quantitatively. The influence of the location and the N concentration of the GaNXAs1-X SCL on compensation of the strain formed on quantum dots （QDs） and the system is also discussed. The reduction effect of SCL on strain of system is analyzed and the vertical alignment probability between the adjacent layers is calculated. Our results can provide a theoretical basis for finding the optimal properties of SCL to realize the high quality multi-QD layer.