Aimed at computation of integer-based image quality assessments, we propose the fixed-point arithmetic operations (FXP) in this paper. Four basic integer-based operations are defined, including, fractional addition, fractional multiplication, fractional division, and fractional square root. Furthermore, four kinds of image quality assessments are measured, including, mean, variance, structure similarity, and peak signal-to-noise ratio. The experiment results demonstrate that the proposed scheme achieves low precision loss, and it needs less computing time than floating-point arithmetic operations (FOP) do in low-level embedded system.